This issue is cultural conditioning.
If this sort of thing is tolerated, it will expand. If it is not tolerated people will come, over time, to accept that gun owners have the same housing rights as blacks and jews. This is also the essence of the current battle over the "religious freedom laws" - is acceptance of gays something on which reasonable people can disagree, or is it something like racial equality in which there is only one socially acceptable "correct" answer? The legislatures in some of the southern starts are working hard to make sure that the former position prevails. (Nobody seems to be asking them if the religious freedom law would allow someone to deny service to an interracial couple if their religion prohibits it).
Not trying to be rude, although I am sure it will sound that way.
To me this line of reasoning boils down to, "It is ok to use the government to trample on a right as long as I do not agree with that right"