Agreed on this comic and in general, but Ship To Ship seems to me to acknowledge sexual orientation in their world is similar-ish to ours, right down to the petty antagonisms between “incompatible” orientations. If anything, I’d say the Oglaf world does “everyone is some flavor/degree of bisexual”. There certainly doesn’t seem to be any bigotry over orientations.
Yeah, I guess calling them bi is more of a projection of our reality onto theirs. I think you’re spot on with it being about stigma (or the lack thereof, rather).