This argument goes right to its ultimate logical conclusions so fast its unbelievable: From the question I just asked it can be presumed I'm 100% fine with discrimination at scale in society. I am not. And yet, should the federal government be allowed to create women's shelters? Or men's bathrooms? Or urinals which are explicitly discriminatory based on your biology? Of course.
Some nuance has to come back to the conversation around discrimination. Honestly, it seems rather simple to me, although I always hold my breath and wait for someone to call me a horrible person: discrimination should be legal, and we should also lampoon and publicly mock bad and stupid discrimination.
If we aren't allowed to mock anything, if we all need to respect each other, then we _need_ anti-discrimination laws. I'd fight for anyone's right to deny anyone else access to their home. I'd still think they're a huge jerk for not being nice to their neighbors.
Nobody has an issue with either of these churches that have such specific audiences, so focusing on White Christians to demonstrate your point probably falls a little flat.
Are there White specific churches? Mennonite churches probably could be classified this way, but it's not because of racial segregation. Comparing any of this to gender just doesn't make sense.