There are two points to undestand here.
1) As Linux gets more populare, the more of this we are going to see. Attackers attack the masses, not the minorities. It is a number game. If you attack 1k people you may get 1 hit. If you accack 100k you may get 100 hits. So the more the to offer, the greater the insentive.
2) Unlike Windows, linux is opensource, so someone is going to find this crap before its too late. This is exacly what happened here. If it were Windows, we may be would have known after it attacked many companies and the attacker would have aleady won.