TBH, what makes me more uncomfortable is the whole tone of your post, OP. The 'discuss' seems to get people's backs up, but more, I'm a bit confused by what feels to be like faux shock?
I mean, you must know by now that people hold strongly, openly homophobic views and that it's not particularly uncommon?
It does get on my nerves that a lot of MNers seem to imagine homophobia is a thing of the past, such that a (rather mild) comment like this is treated as the shocking exception.
It just isn't.
It's probably not the worst thing a lot of gay people have heard in the past year, maybe not the past month.
If you dislike it and have energy or inclination to discuss it with this woman, go for it. But handwringing on social media, where you obviously imagine most people will agree with you it's terrible, just seems a bit self-indulgent to me. Yes: you are a wonderful, caring person. Much better than her. Does that help you?
I get that I am being a little harsh and you probably mean well. But you do sound awfully shocked by a pretty mainstream view.