I find the NYT’s answer homophobic.
The excessive overreaction shows that they deep down feel that homosexuality is wrong. If they really thought it was OK, they wouldn’t have any problem with the putative brother-in-law bringing it up for discussion.
Second, they weren’t even willing to consider the possibility that the sister might be a lesbian and that the living arrangement is one of mutual convenience. This again shows latent homophobia.
They should send the writer to diversity training until he acknowledges his covert feelings.
There it is.