He was born and brought up in this village, but after staying and studying abroad his childhood friends seem backwards to him; he _ this place now.
He had lived in this city all his life but whenever he gets a chance he starts counting the flaws. He thanklessly _ his homeland.
It might even apply to a situation like say you party every weekend but if somebody else does the same you criticize them.
Note: Read title: act of crticizing one's own homeland/city/country
I can use words like criticize, betray or badmouth in my sentences, but I am looking for more like an idiom or phrase or even a proverb, that may or may not fit into my sentences but explains the intent.
The intent here is being a hypocrite to an extent, yes but there's an addition of viewing one's own homeland or people as backwards(where I don't think that person has changed, they are just trying to show off).
In hindi there's a saying "jis thali me khaya usme ched kiya" which means destroying the plate in which you are served. I'm kinda looking for an english analog for this proverb. I thought "don't shit where you eat" would be the close but it was hilarious to find out it's meaning and of course that it's nowhere close.