Is a graduation ceremony avoda zara?

I think the phrase is “Hukas Goyim”. The only aspect of an American school graduation that might be Avodah Zarah would be the statement by a usually Christian clergy person (the “invocation”)-and if that is your standard many government functions would be banned. There is also some reason to suspect that Yidden have historically celebrated accomplishments (more likely with food and drink than with a boring ceremony).

Ask your LOR,
Masores Moshe Volume 2 says that it’s a problem of chukos hagoyim…

The Targum Yonasan says that on shemini atzeres we are happy we can go back to the house. I explained that sukkah is a learning process for the whole year with the ushpezin as teachers such that shemini atzeres is graduation day. There is no avoda zara involved to recognize one’s accomplishments for the rest of one’s life with a diploma. Yeshivas have also graduation ceremony of elementary school and high school.

@OP, no one is forcing you to do anything, worry about yourself not other people, I skipped my college graduation and went to my daughter graduation.
PS I envy you, that is is the only thing in your life that worries you.

Maybe academic dress is similar to what Jews consider scholarly dress also? Long robes and sleeves are the sign that the person is not engaged in manual labor and does not need to run fast in his business. Not that different from scholarly costumes yeshiva students wear our days.

I skipped high school, undergrad, MBA and Law School graduations.
Nothing more boring than to be in the heat in a polyester gown and mortarboard listening to endless speeches

I worked out a speech for one of the kids for a middle school graduation – about a difference between “graduation” and a “siyum”.

Graduation comes from latin “step” so you step out of what you were doing. Siyum says that we are going to return to the maseches again

Wolfmusings and anyone else

So what is the honest answer to where the minhag of making a vach nach seuda the night before a bris come from?

Can anyone tell me and how many generations back does this minhag go from?

I know of a klal that when minhag goyim is based on a sevorah, we are allowed to follow, but not when it is irrational. So, it might depend on a degree:
having a ceremony celebrating ability to become a medical doctor sounds rational. Celebrating spending $200K on achieving bakiyut in gender studies – irrational.