I can't say I've been following this case closely nor am I a lawyer but... it sounds like the Pirate Bay guys are saying "we don't own the [possibly] criminal e

I can't say I've been following this case closely nor am I a lawyer but... it sounds like the Pirate Bay guys are saying "we don't own the [possibly] criminal enterprise; we just run it." If the organization's activities are deemed illegal wouldn't anyone facilitating these activities be liable? Why does it matter whether they "own" it? How are, say, mafia bookies or web designers in the employ of illegal gambling operations websites treated under the law?