Of the 5 reasons, the first one is the most important: tribalism. It is what also explains why they vote against their own interests: the interests of the tribe is stronger. The way to enforce that, as noted by some people in this very thread, is that if you don’t support the tribe, you will alienate your family and friends.
It is a classic manipulation trick, historically documented in religions and cults. Nobody is immune to it.
What should worry us is that the Internet as made this kind of manipulation both covert and possible on a large scale by automatic systems.
