A couple of relevant points.
Being openly gay is not the same as engaging in the relevant issurim, and there are levels of issurim which are less than actual arayos.
I don’t know if people are gay because of genetics; because of genetic predispositions and environmental triggers; only because of environmental triggers; only or partially because of other issurim they did; or only or partially because of other hashkafos they have. But I don’t think it really matters. Because I do know that regardless of the above, they aren’t making a conscious or easily reversible choice. The same way nobody makes a conscious choice to be depressed even though it may be due to any of the above factors or more.
Thus, there is such a thing as being gay, which is something I don’t think should be looked down on–in itself. If they are doing issurim, that is wrong. And if they are advancing hashkafos that challenge the Torah, that is also wrong.
So perhaps this minyan is wrong (I don’t have enough info), but some of this thread is also wrong.