Snowden may be a hero to many, but he is also legitimately accused of breaking laws in a criminal fashion.
I don't see anything wrong with interfering with the travel of fugitives from justice. Even if there are doubts about the "justice" getting applied here, just ignoring the US justice system is probably not the right way to go either.
Yes and there is also a difference between the way US justice operates and let's say Scandinavian. They do not turn their countries into prison planet where collusion between government and private enterprise encourages large scale abuse.