I don't need to understand why doing things weird will make me unpopular (it signals that I do not subscribe to the group norms), I just need to know that they do, and so only do them in private.

Often true, but note that if you do not understand the reason for some rule, you run the risk of getting into a situation where you think it should apply but it doesn't, or vice versa.

I agree with your overall point, however.