- Yakkov was the first to get the word, not Dina's brothers.
בראשית לד ה-ז
וְיַעֲקֹ֣ב שָׁמַ֗ע כִּ֤י טִמֵּא֙ אֶת־דִּינָ֣ה בִתּ֔וֹ וּבָנָ֛יו הָי֥וּ
אֶת־מִקְנֵ֖הוּ בַּשָּׂדֶ֑ה וְהֶחֱרִ֥שׁ יַעֲקֹ֖ב עַד־בֹּאָֽם׃
וַיֵּצֵ֛א חֲמ֥וֹר אֲבִֽי־שְׁכֶ֖ם אֶֽל־יַעֲקֹ֑ב לְדַבֵּ֖ר אִתּֽוֹ׃
וּבְנֵ֨י יַעֲקֹ֜ב בָּ֤אוּ מִן־הַשָּׂדֶה֙ כְּשָׁמְעָ֔ם
וַיִּֽתְעַצְּבוּ֙ הָֽאֲנָשִׁ֔ים וַיִּ֥חַר לָהֶ֖ם מְאֹ֑ד כִּֽי־נְבָלָ֞ה
עָשָׂ֣ה בְיִשְׂרָאֵ֗ל לִשְׁכַּב֙ אֶת־בַּֽת־יַעֲקֹ֔ב וְכֵ֖ן לֹ֥א
Jacob heard that he had defiled his daughter Dinah; but since his sons were in the field with his cattle, Jacob kept silent until they came home.
Then Shechem’s father Hamor came out to Jacob to speak to him.
Meanwhile Jacob’s sons, having heard the news, came in from the field.
The men were distressed and very angry, because he had committed an outrage in Israel by lying with Jacob’s daughter—a thing not to be done.
Obliviously, Yakkov was not happy about it. I believe that the Torah does not write Yakkov's reaction, as contrast to Shimon and Levi aggressive reaction.
Yakkov had an argument with Shimon and Levi at the aftermath, and they get to say the last words. Does it mean that they are right? Does it mean that Yakkov approach is wrong? Those two questions are open for discussion.