it is because the werewolves of skyrim are its true gaurdans. the silver hand are trying to make skyrim weak for the thalmor to invade with out its werewolf protectors.

silverhand are the bad guy's mostly because you are a werewolf and they are werewolf hunters. Just really bad ones.

Edit: I think they are just bandits that just decided to run around killing werewolfs for money

http://oyster.ignimgs.com/wordpress/www.ign.com/79/2012/04/hahaha_no.gif



They carry Vampire Dust due to it having "Cure Disease" as one of the effects. They carry a lot of ingredients with Cure Disease effects, due to them believing that Lycanthropy can be caught through contact with the Werebeast.

@OP, I once found a Khajiit in their holding cells. In another I found a Horse.

This should tell you effective they are at deciding whether one is a Werebeast or not.

The werewolves are supernatural i.e. unnatural therefore they believe they must be destroyed. They are a single goaled version of the vigilants of Stendarr (except more banditish).

So basically they could be bandits due to there bad decision making

the Silver hand was one of the major dissapointments in the game for me, along with the companions questline. I really expected more than plain bandits with silver weapons...

Because the Dovahkin is destined to join the Companions and, therefore, cannot join the Silver Hand. Just like the Dovahkin cannot join a band of bandits or the Forsworn. Simply against the stars.