A couple problems with the views those people have though. The first is that there *are* people who don’t have a gender identity, the agendered, and that group has to deal with their own unique struggles that cisgendered do not struggle with. So rejection based on on those grounds is problematic.

The second is that it is a neigh undeniable fact that the majority of people are assigned a gender at birth. This is not some mysterious unknown metaphysical process. There is literally a checkbox that a human being checks (usually a doctor) that assigns the gender at birth. The doctor is human, and as such, is subject to human fallibility. To claim this is not the case is to claim that humans are infallible, which is quite the bold claim indeed.