I can on speak as a gay male couple, but our experiences on three cruises have all been wonderful. No issues with our tablemates. No issues with any of the servers, cast or crew. We were even selected to participate in "Match Your Mate" on one cruise based on the cheers of the crowd (and we won).
The only ... slightly "negative" incident I can recall is one night we were walking back to our room (simply walking side by side in the narrow-ish corridor) and a presumably heterosexual couple walking behind us who had (again presumably) been drinking said (more loudly than I think they intended) something along the lines of having seen so many of "those types" (i.e. gay couples) on the cruise.