The fight over Southie’s St. Patrick’s Day Parade got frosty yesterday, with Boston Beer Co. pulling its longtime sponsorship from the parade over the organizers’ refusal to let gay veterans march — and one Southie bar fighting back with a vow to boycott the brew.

“Sam Adams doesn’t support South Boston. They don’t want to support veterans like my father and uncle, so they can go sell their beer elsewhere,” said Tommy Flaherty Jr., a lifelong Southie resident whose father and uncle own the landmark Cornerstone Pub & Restaurant on West Broadway.

Flaherty Jr. said he and his father, Thomas Flaherty Sr., 70, and his uncle John Flaherty, 81, were “taken aback” when they learned yesterday afternoon from reading that the brewing behemoth pulled its sponsorship, so they decided not to sell Sam Adams indefinitely.