Honestly, I never heard of such a thing as a “topless bar”? Do you mean a strip club?
Would I? Probably not. Does that means it’s assur to do so? No
@AviraDeArah
Actually Rav Moshe applies that gemara to someone who needs to go to the beach and would be around pritzus, not just walking through. See Igros Moshe Even Haezer 1:56, especially the beginning and end of the teshuva.