By checking for fealty to the false “stolen” narrative at the outset, Trump’s allies aren’t simply weeding out people who disagree, they’re weeding out people who won’t acquiesce to the Trumpian approach to reality. They’re not just getting rid of people who won’t go along on this one subject; they’re getting rid of people who won’t go along in general.
This is exactly how cult leaders operate.
You have to reject the same reality as the cult, or you’re part of the “out” group.