tribes don't reproduce; people do.
Values reproduce as the people who hold them reproduce, plus as others adopt those values, minus as those who hold those values drop them.
But the US was supposed to be a country where values mattered more than tribe. "We hold these truths to be self evident", and all that, and if you accepted the values, you belonged. That was an imperfect ideal, but it was the ideal until rather recently. I'm not sure to what degree it still is.
And we are of course allowed to change that, if that is what the people want, but a minority should not make that decision on behalf of the whole.