LOL! The Great Purge indeed. No, no revenge going on at all there.

DarthBo:
Personally, if Luke can forcechoke guards and slice anyone who gets in his way with his lightsaber, I don't see why he wouldn't be able to take revenge. Anakin (no longer Vader) sure takes revenge on Palpatine.

Exactly who does Luke "slice" who gets in his way? Star Wars? No-one. Empire? No-one. Jedi? No-one, he just defends himself in a fight on the Sail Barge, then duels with Vader. Hardly a raging psychotic. And if you don't know why Luke won't take revenge yet the Sith do, I wonder what exactly you think the difference between the two is. And Anakain is saving his son and restoring good to the galaxy when he kills Palpatine. It's not simple revenge for what he's done to him personally.