The "Republicans backed the moderate therefore he's a Republican" argument gets used in so many races and it's always such a weak argument. In any race with two candidates separated by a clear ideological line, both candidates are going to claim everyone on their side of that line. In this race, where it was Dem-vs-Dem, Brown carried everyone to the right of the line, which included many Republicans (not that there are very many in Buffalo).
It's the same way here in Seattle. All twenty Republicans in Seattle are backing Bruce Harrell because he's closer to them than Lorena Gonzalez. That doesn't make him a Republican.
Absolutely. But for some "progressive idiots" if you are not with them in 100% of cases - you are already "Trump Republican". No need to talk with people who doesn't have any brains...