You're trying to bash gays for something irrelevant because you've lost the relevant argument.
Be that as it may... is he right?
No he's not right. A gay couple doesn't have to go around buying dozens of cakes from bakeries run by people of all possible religious denominations to prove some insane accusation by a RWnut isn't true.
That is absurd even for you people.
Well, given that Muslim religious beliefs, and related cultural practices within the regions where Islam is dominant, seem to anathematize and shun homosexuals to an extent unknown at-large in The West, perhaps it's time that the LGBT community puts this so-called new-found Egalitarianism to the test in a Muslim-centric setting.
I mean, after all, the LGBT community has become highly organized and proactive in recent years, and they have been known to seek-out publicly-declared opponents of their agenda, to public chastise them and to attempt to bait them into such acts as refusal-of-service, so, pursuing Muslims for purposes of such testing is consistent with both their agenda and past behaviors.
An individual couple does not have to do such things, but, one would think, in the interests of complete fairness, that the activist element(s) of their movement, would be obliged to put such resistance to the test, within all frameworks, not just those other than Islam.
So...
Perhaps the idea - and allegations of hipocrisy and intellectual cowardice - are not so far off-the-mark, after all?
The whole idea sounds like great fun... let's see the LGBT community at-large make a concerted effort to test Muslim business owners, as well.