Simcha: Thanks for putting it better than I did.
Joe, the difference between the sins you mention and being gay is a) being gay isn’t a sin- homosexual activity is a sin. So you will have many Orthodox people who are gay whether you know it or not, who will not act on it but still identify with other people struggling in the same way. And b) something like adultery does have another outlet, ie marrying someone available. Gay people don’t have this option.
That doesn’t mean I support the parade. I agree, the parade does explicitly support those who actually are sinning, and while I have no control over whether Israel has such a parade or not, I can still disapprove. But there are Orthodox gay people who identify themselves as gay even if they will never enter a forbidden relationship because it is a common life experience and struggle that puts them at odds with the world at large and kal vachomer the frum community, and that’s undeniable. Should they march in the parade? That’s their own cheshbon. Would I march in support? No, because I don’t agree with the rationale behind the parade. Do I think it’s weird that being gay is an identity, particularly in the Jewish world? Honestly, not really.