Inform a brother.
(oh god, I'm "Just asking questions")
Is Southie an ultra conservative haven within Mass.? There seems to be some unspoken knowledge as to why bigotry against gay veterans is "unsurprising".
It's not even conservative, still likely went hard Democrat in every election. It's traditionally been a working class Irish Catholic Democratic suburb of Boston, and then in the 1990s-2000s, a huge influx of bros (I mean this in like the white, middle-class college-grad Lacross bros way; or like the American equivalent of a "Chav / Chavette") moved there because it was affordable and convenient. So you'd get a mix of that classic blue collar Democrat but "I'sweaah bro this queeah was tryna fuck me at dunks yestaday" stereotype with recent college grads who are definitely Democrats, but personally xenophobic and homophobic.
Very pro-Democrat, but represents a sort of pro-labor, working class Irish democrat that has run cities like Providence or Boston for a century.
The gay people marching in the St. Patrick's day parade is a mix of this... Xenophobic, overly paroquial, "My mam's catholic bro so no fag shit," with trashy drunks. The South Boston St. Patrick's Day parade sucks.
*edit*
Though as someone else pointed out, my stereotype of your average South Bostonian probably isn't accurate anymore. This was my impression going to South Boston from like 2002-2012, but I really haven't hung out there in half a decade aside from running or passing through.