You ask a fantastic question!
The book Sichas Malachei Hashores was written by Rav Tzadok HaKohen of Lublin, where he expounds sources in the Bavli, Midrash, Zohar, and Yerushalmi pertaining to the practice of angels and their relationship to man.
In the section on Yerushalmi he tackles this Yerushalmi.
In creation we see that when everything was called Hebrew names, the given name represents its essence, and there was a reason for every name, no name was named by random choice. Such as in Genesis (2:23) when Adam names Eve "אישה" -
Then the man said, “This one at last Is bone of my bones And flesh of
my flesh. This one shall be called Woman, For from man was she taken.”
And if the explanation for a certain name is not mentioned explicitly in the Torah, it is at least explained by the sages. Thus indeed angels could be named individually according to the role that they come to play and task they come to fulfil, so why weren't they clearly named from the beginning? He cites a Midrash. The Midrash (Bamidbar Raba 10) about Manoach, when the angle came to inform him and his barren wife that they will give birth to Shimshon, Manoach asks of his name. The angel replies (13:18):
“You must not ask for my name; it is beyond me!”
The Midrash explains that the angel could not name himself as his name depends on Hashems mission for him, which is dynamic.
Therefore in previous times angels are not named explicitly due to Godliness being revealed within Israel, the angels were constantly changing names, Hashem always commanding them to change forces going "beyond" their nature. However, with the exile to Babylonia, miracles and changes to nature becoming a very rare occasion, the angels could be called static names.
I recommend opening this inside, he has a wonderful and profound in-depth explanation over there about the role of angels.
