If you count oral, that's probably true. Something one of my uncles once said sort of sums up an attitude among a fair number of straight guys: "A mouth is a mouth is a mouth, but if you want to get laid get a broad" (the language sort of dates the saying). So if a gay guy wants to go down on someone, it isn't totally hard to find a straight guy who's up for it.
I also don't think it is a big deal for gay guys being sucked by women.

