Let's face it, Paladins in D&D are assholes. By assholes, I mean massive assholes. They have to be that way because the game rules over the editions generally encouraged the behavior. Structurally, the Paladin had to be an asshole to avoid getting screwed over himself.
Paladins are a special class in two ways. First, they are special because they are better than the normal person, given special powers. They only keep these powers as long as they keep their behavior regulated. They must always achieve their ideal. However, the party that they serve with is not bound by such strictures, and their actions can create a situation where the Paladin, by not blocking a behavior, condones a behavior by inaction.
Second, Paladins are the only class that lose their powers. As others can cause them to lose their powers, Paladin players must act to regulate their fellow players lest their paladin gets screwed over. Given that the average D&D have a challenged idea of what constitutes good (including genocide), you can see that the Paladin player has been handed a nearly impossible task. At almost every move, he will need to oppose the actions of his party fellows.
You can see where this leads, because you typed in "asshole paladins" and found this blog post.
So, what's the solution? The first solution is to not have a class that gets hosed over through the behavior of his own party. The easiest way to accomplish that is to simply throw out the rule that Paladins can fall from grace. Problem solved. At a minimum, a Paladin's abilities should be no easier to lose than a Cleric's. If this seems counter intuitive, remember that a Cleric can do anything and the rules don't care. Nothing short of DM fiat can reign in his abuses. Second, if the Paladin does lose his specialness, the class needs a clear path to recovery that is less onerous than the death rules. Unfortunately, it's actually easier to come back from the dead than it is to recover your Paladin abilities. (I may be overstating my case here, but not by much.)
So, if you have an asshole Paladin at your table, look at the rules. Most likely, the player is merely trying to survive an impossible situation.
There is a second situation in which a paladin is an asshole: that's when the player is the asshole. The class merely becomes the conduit at that point. This problem is best rectified by removing said player.