It doesn't matter to me if it's gay or straight. Minimal PDA is fine but excessive snogging and over the top lovey dovey stuff - I don't really want to see that.
It does depend on how public it is. Middle of town I don't need to see a couple practically having sex on a bench. If they are in a secluded part of a park and are cuddling on the grass but there is plenty of space to move away (like dog walkers, play area, sports pitch, pond etc all in the same park) then it's less public so it's more tolerable
I have no specific problems with gay PDAs, but I don't like PDAs for the sake of eliciting comment, gay or straight ("we're sucking face in the street so other people can see us"), but hand-holding and reasonably quick kisses are fine.