The Egyptian people didn't react violently because nearly the entire population were also slaves according to the narrative and laws the Torah lays out for us.
Genesis 47:12-27
יב וַיְכַלְכֵּל יוֹסֵף אֶת-אָבִיו וְאֶת-אֶחָיו, וְאֵת כָּל-בֵּית
אָבִיו--לֶחֶם, לְפִי הַטָּף. 12 And Joseph sustained his father, and
his brethren, and all his father's household, with bread, according to
the want of their little ones. יג וְלֶחֶם אֵין בְּכָל-הָאָרֶץ,
כִּי-כָבֵד הָרָעָב מְאֹד; וַתֵּלַהּ אֶרֶץ מִצְרַיִם, וְאֶרֶץ כְּנַעַן,
מִפְּנֵי, הָרָעָב. 13 And there was no bread in all the land; for the
famine was very sore, so that the land of Egypt and the land of Canaan
languished by reason of the famine. יד וַיְלַקֵּט יוֹסֵף,
אֶת-כָּל-הַכֶּסֶף הַנִּמְצָא בְאֶרֶץ-מִצְרַיִם וּבְאֶרֶץ כְּנַעַן,
בַּשֶּׁבֶר, אֲשֶׁר-הֵם שֹׁבְרִים; וַיָּבֵא יוֹסֵף אֶת-הַכֶּסֶף,
בֵּיתָה פַרְעֹה. 14 And Joseph gathered up all the money that was
found in the land of Egypt, and in the land of Canaan, for the corn
which they bought; and Joseph brought the money into Pharaoh's house.
טו וַיִּתֹּם הַכֶּסֶף, מֵאֶרֶץ מִצְרַיִם וּמֵאֶרֶץ כְּנַעַן,
וַיָּבֹאוּ כָל-מִצְרַיִם אֶל-יוֹסֵף לֵאמֹר הָבָה-לָּנוּ לֶחֶם,
וְלָמָּה נָמוּת נֶגְדֶּךָ: כִּי אָפֵס, כָּסֶף. 15 And when the money
was all spent in the land of Egypt, and in the land of Canaan, all the
Egyptians came unto Joseph, and said: 'Give us bread; for why should
we die in thy presence? for our money faileth.' טז וַיֹּאמֶר יוֹסֵף
הָבוּ מִקְנֵיכֶם, וְאֶתְּנָה לָכֶם בְּמִקְנֵיכֶם--אִם-אָפֵס, כָּסֶף.
16 And Joseph said: 'Give your cattle, and I will give you [bread]
for your cattle, if money fail.' יז וַיָּבִיאוּ אֶת-מִקְנֵיהֶם,
אֶל-יוֹסֵף, וַיִּתֵּן לָהֶם יוֹסֵף לֶחֶם בַּסּוּסִים וּבְמִקְנֵה
הַצֹּאן וּבְמִקְנֵה הַבָּקָר, וּבַחֲמֹרִים; וַיְנַהֲלֵם בַּלֶּחֶם
בְּכָל-מִקְנֵהֶם, בַּשָּׁנָה הַהִוא. 17 And they brought their cattle
unto Joseph. And Joseph gave them bread in exchange for the horses,
and for the flocks, and for the herds, and for the asses; and he fed
them with bread in exchange for all their cattle for that year. יח
וַתִּתֹּם, הַשָּׁנָה הַהִוא, וַיָּבֹאוּ אֵלָיו בַּשָּׁנָה הַשֵּׁנִית
וַיֹּאמְרוּ לוֹ לֹא-נְכַחֵד מֵאֲדֹנִי, כִּי אִם-תַּם הַכֶּסֶף
וּמִקְנֵה הַבְּהֵמָה אֶל-אֲדֹנִי: לֹא נִשְׁאַר לִפְנֵי אֲדֹנִי,
בִּלְתִּי אִם-גְּוִיָּתֵנוּ וְאַדְמָתֵנוּ. 18 And when that year was
ended, they came unto him the second year, and said unto him: 'We will
not hide from my lord, how that our money is all spent; and the herds
of cattle are my lord's; there is nought left in the sight of my lord,
but our bodies, and our lands. יט לָמָּה נָמוּת לְעֵינֶיךָ,
גַּם-אֲנַחְנוּ גַּם אַדְמָתֵנוּ--קְנֵה-אֹתָנוּ וְאֶת-אַדְמָתֵנוּ,
בַּלָּחֶם; וְנִהְיֶה אֲנַחְנוּ וְאַדְמָתֵנוּ, עֲבָדִים לְפַרְעֹה,
וְתֶן-זֶרַע וְנִחְיֶה וְלֹא נָמוּת, וְהָאֲדָמָה לֹא תֵשָׁם. 19
Wherefore should we die before thine eyes, both we and our land? buy
us and our land for bread, and we and our land will be bondmen unto
Pharaoh; and give us seed, that we may live, and not die, and that the
land be not desolate.' כ וַיִּקֶן יוֹסֵף אֶת-כָּל-אַדְמַת מִצְרַיִם,
לְפַרְעֹה, כִּי-מָכְרוּ מִצְרַיִם אִישׁ שָׂדֵהוּ, כִּי-חָזַק עֲלֵהֶם
הָרָעָב; וַתְּהִי הָאָרֶץ, לְפַרְעֹה. 20 So Joseph bought all the
land of Egypt for Pharaoh; for the Egyptians sold every man his field,
because the famine was sore upon them; and the land became Pharaoh's.
כא וְאֶת-הָעָם--הֶעֱבִיר אֹתוֹ, לֶעָרִים: מִקְצֵה גְבוּל-מִצְרַיִם,
וְעַד-קָצֵהוּ. 21 And as for the people, he removed them city by
city, from one end of the border of Egypt even to the other end
thereof. כב רַק אַדְמַת הַכֹּהֲנִים, לֹא קָנָה: כִּי חֹק לַכֹּהֲנִים
מֵאֵת פַּרְעֹה, וְאָכְלוּ אֶת-חֻקָּם אֲשֶׁר נָתַן לָהֶם
פַּרְעֹה--עַל-כֵּן, לֹא מָכְרוּ אֶת-אַדְמָתָם. 22 Only the land of
the priests bought he not, for the priests had a portion from Pharaoh,
and did eat their portion which Pharaoh gave them; wherefore they sold
not their land. כג וַיֹּאמֶר יוֹסֵף אֶל-הָעָם, הֵן קָנִיתִי אֶתְכֶם
הַיּוֹם וְאֶת-אַדְמַתְכֶם לְפַרְעֹה; הֵא-לָכֶם זֶרַע, וּזְרַעְתֶּם
אֶת-הָאֲדָמָה. 23 Then Joseph said unto the people: 'Behold, I have
bought you this day and your land for Pharaoh. Lo, here is seed for
you, and ye shall sow the land. כד וְהָיָה, בַּתְּבוּאֹת, וּנְתַתֶּם
חֲמִישִׁית, לְפַרְעֹה; וְאַרְבַּע הַיָּדֹת יִהְיֶה לָכֶם לְזֶרַע
הַשָּׂדֶה וּלְאָכְלְכֶם, וְלַאֲשֶׁר בְּבָתֵּיכֶם--וְלֶאֱכֹל
לְטַפְּכֶם. 24 And it shall come to pass at the ingatherings, that ye
shall give a fifth unto Pharaoh, and four parts shall be your own, for
seed of the field, and for your food, and for them of your households,
and for food for your little ones.' כה וַיֹּאמְרוּ, הֶחֱיִתָנוּ;
נִמְצָא-חֵן בְּעֵינֵי אֲדֹנִי, וְהָיִינוּ עֲבָדִים לְפַרְעֹה. 25 And
they said: 'Thou hast saved our lives. Let us find favour in the sight
of my lord, and we will be Pharaoh's slaves' כו וַיָּשֶׂם אֹתָהּ
יוֹסֵף לְחֹק עַד-הַיּוֹם הַזֶּה עַל-אַדְמַת מִצְרַיִם,
לְפַרְעֹה--לַחֹמֶשׁ: רַק אַדְמַת הַכֹּהֲנִים, לְבַדָּם--לֹא הָיְתָה,
לְפַרְעֹה. 26 And Joseph made it a statute concerning the land of
Egypt unto this day, that Pharaoh should have the fifth; only the land
of the priests alone became not Pharaoh's. כז וַיֵּשֶׁב יִשְׂרָאֵל
בְּאֶרֶץ מִצְרַיִם, בְּאֶרֶץ גֹּשֶׁן; וַיֵּאָחֲזוּ בָהּ, וַיִּפְרוּ
וַיִּרְבּוּ מְאֹד. 27 And Israel dwelt in the land of Egypt, in the
land of Goshen; and they got them possessions therein, and were
fruitful, and multiplied exceedingly.
The only reason the Israelites were not immediately made slaves was because Joseph sustained them during the famine and the very harsh policies he enacted. According to these laws most Egyptians would become slaves to Pharaoh, would have had 1/5 of their food taken away, and would have their population shifted based on the needs of the government. The only ones initially exempt from this were the Israelites due to the influence of Joseph. But it also seems like this "special treatment" from Joseph led to their being a growing unrest against the Israelites not just from Pharaoh, but from a large swathe of the Egyptian populace as well. We see hints of this because Pharaoh needs to ask his people to do evil against the Israelites, he can't just order his men to do it because then it would make him look too bad. Instead he tries to craftily reduce the Israelite numbers, and tries to get the local population to participate in it.
Exodus 1:22
כב וַיְצַו פַּרְעֹה, לְכָל-עַמּוֹ לֵאמֹר: כָּל-הַבֵּן הַיִּלּוֹד,
הַיְאֹרָה תַּשְׁלִיכֻהוּ, וְכָל-הַבַּת, תְּחַיּוּן. {פ} 22 And
Pharaoh charged all his people, saying: 'Every son that is born ye
shall cast into the river, and every daughter ye shall save alive.'
{P}
I bring this up because this event probably ended up being well known amongst most people in Egypt, even amongst Egyptians who didn't participate in these genocide. And I would argue it's this event that leads to the Egyptian population being understanding and compassionate toward the Israelites, even as these plagues cause them problems. My argument is based on the first plague that God sends against the Egyptians, which is a twofold statement. The nile will turn red with blood so that way the Israelites understand God knows and saw what happened with them, and so that way the Egyptians understand that this murder they participated in as a country all those years ago is why these plagues against you are happening now.
It also helps explain why there was a great mixed multitude that left Egypt with the Israelites. These peoples were probably also slaves, and are also aware that God is defending a slave people against injustice, for which Egypt as a country is guilty.