St. Patrick's Day isn't only in NYC, but, yes, it's generally an excuse to drink beer. It is also a celebration and appreciation of Irish culture. Some Irish Americans take that pretty seriously.
Whether you like that comparison or not, you misjudge that cultural history month celebrations are divisive here. They're simply not. They're rather a lot more like wallpaper, and pretty easy to ignore. Schools and public TV, etc., do special segments, generally historically-centered. In the US, history lessons/books have tended to be very euro-centric, both historically and ethnically, so these "cultural awareness months" are meant to go some way to filling in some blanks. And, though the Republicans have recently taken the position that a lot of history is too dangerous to be taught, or offensive, I don't see how information is ever a bad thing. You're are simply wrong that it's posited as in contrast to the horrible white people. Anyway, most people can easily ignore these things. It's not like the grocery store celebrates Black History Month, or most TV does any of them. But they are a recognition of some peoples' being more over-looked, historically. There is pride in stories that reflect one's history. Nothing wrong with that.