It's not "factually incorrect". We are talking about 80% or so hating gays, 19% being indifferent, and 1% actually being gay. Sure numbers could be off. Does it matter?
Think about all the terror attacks we've had over the past couple years. People guess and usually are correct that it's a Muslim.
The fact that maybe 10% of a certain culture are benign, when the other 90% are hostile makes them the exception to the rule, and the reason why we NEED VETTING.