The fact of deciding when are double standards enormous is quite subjective. A double standard being bigger than the other may depend of how many people are affected by them, for example. Such bigger double standards don't neccesarily mean they are worse than the smaller one, though.

Anyway, I think double standards are as common as other unfair applications of principles on the society, and even though they are despicable for most people, without it, society as we know it wouldn't have developed.