This episode is about justice, and the unwillingness of one culture to trust another's way of dispensing it. And unfortunately, American Indians had a reason for not trusting it.
Yes, Kioga (excellently played by Teno Pollick) doesn't have much dialogue in the show, but in my opinion it is a well-written piece. He is tenacious in his desire to exact justice...and it is justice, even though some may call it vengeance. There may be a fine line, especially when repercussions of wrongdoing are administered by those who suffered from the actions. But when objective parties - those who didn't experience any suffering - want to administer the same justice, a life for a life (as Matt Dillon did), it is justice.
I think it was well-acted by all involved! I've always appreciated the talent Neville Brand had in portraying seedy characters, he was a top-notch actor! His looks and voice helped in that regard.