I agree that it's not the best course of action. I agree that it's not very constructive.

However different people react in different ways. I don't believe OP thinks that this block was permanent, nor do I think that her BF is going to make it permanent.

The fact is he was upset, he got backed into a corner and instead of taking a constructive approach, he took an unreasonable one. Which sometimes people do when they are emotional and backed into a corner.

Blocking is unreasonable and detrimental to the relationship. But it's something that should be talked about and a better solution talked about. Unless this is repeat behaviour, breaking up would be a rather extreme action in my opinion.