There is good research that shows that we have reached a point where, when our stand on issues conflicts with our party identity, we are now more likely to change our policy positions than we are to change our party affiliation. Here’s an Amazon link to a book that does a good job explaining where we are and how we got here: Uncivil Agreement
It's well studied that politics are increasingly becoming a point of identity for everyone; this is not limited to reddit:
https://www.amazon.com/Uncivil-Agreement-Politics-Became-Identity-ebook/dp/B07C13LC3N