In praise of bigotry (sortof)
Bigotry is the tribal-boundary, us-rather-than-them emotion, and it can be very ugly. Examples include nationalists who despise people from other nations, religious people who greatly prefer people from their own religion, academics who take sides in large (e.g. humanities vs. sciences) or small (e.g. bayesian vs. frequentist) academic tensions.
There is, however, a virtue in knee-jerk, unjustified, preemptive judgements. If you aquire some random bigotries regarding what are worthwhile topics or domains and then study everything, pruning away lines that lead into those topics or domains, then you may acquire a unique angle or take on things. If everyone in a group first chooses some random bigotries for themselves and then studies everything else, the group can acquire diversity, which (sometimes) is very advantageous.
This justification of 'why bigotry' is self-limiting, in that it also justifies tolerance. If someone is pursuing something (e.g. object orientation) that you have personally prohibited, that doesn't make them wrong or bad. If you are advising someone that they should study something (e.g. Marxism), and they say they won't or cannot, that doesn't necessarily make them recalcitrant or antisocial.
The key is that the group needs to decide on action (as opposed to study/thinking), based on public argumentation from a public stance of non-bigotry. When someone gets up to speak, they don't need to (probably cannot) change their mind, however, if they are limited in what forms of argument they can put forward, then the group may be able to make a better decision than any of its members. If people systematically pursue having the same opinion, then they will have less public argumentation, and probably will not be able to take advantage of diversity of viewpoint.