Big difference between Rondo and Wade...
http://www.youtube.com/watch?v=vfuJS0SBSac&feature=related
So I guess this means that wade is weak like Paul Pierce, because they both needed wheel chairs for seemingly minor injuries? That really makes no sense.
Paul had a knee injury, you might not want him walking around. Seems a little different, but I'm no doctor.
Fact is, it's the playoffs. Wade didn't TRY to injure Rondo, or it would have been a LOT worse. He definitely wanted him to know that he wasn't going to let him go wherever he wanted, and he may have even been fine with hurting Rondo. I honestly don't think there's anything wrong with that. He deserved a flagrant for the play, but thats it. Wade is not a dirty player.
So he drags Rondo down on purpose and he's fine with hurting Rondo but that doesn't meet your description of a dirty player? That's a fairly high threshold.
If a doctor thinks a player could be at risk walking around on an injured leg...he'll call for a chair. If a doctor feels a player could be at risk due to passing out due to pain or other less visible symptom of an injury...he'll call for the chair. Either way, they were both seemingly minor incidents, where chairs (usually reserved for more major incidents) were called for. We dont have any reason to think either player was responsible for the chairs to be called. Both situations are comparable, and both players should be ridiculed or justified the same.
And yes...I think it takes more to be a dirty player. Dirty players try to injure people. Theres a big difference between "hurt" and "injure", and I dont think Wade intended to do either to Rondo. It was a freak injury. The two players were tangled up. Wade did most of the tangling, but Rondo wasn't just there trying to get free either. Even if Rondo had his hands up in the air to get free, and Wade brought him down, I wouldnt have a big issue with it given the context (a pivotal game, in an overall physical playoff series, between two rivals). Players are ALWAYS fine with hurting their opponents. That doesnt mean they TRY to injure them. It just means that if your opponent is hurt as a consequence of the 2 of you competing physically, it comes with the territory. The play where Wades shoulder was hurt for example...do you really think the other team felt bad? Should they have? Thats the nature of competing in contact sports. Fact is, I dont remember anyone not currently losing to his team, ever saying that Dwayne Wade played dirty. It should have been called a flagrant 1, but beyond that it should be a non issue.
the bottom line is, unnecessary contact after the play away from the ball is dirty, regardless of intent to injure
By that definition, anytime a player got in another players face and bumped heads, or pushed, would be a "dirty play"...I guess that would mean we'd have to add Pierce (and about 100 other players this year) to the list of "dirty players" 
Those are dirty plays, including Pierce's "head brush" and players usually get technicals for them. That's what techs are for, and they keep the game in order and prevent further problems. Not giving techs to Wade for the crap he pulled earlier in the series has lead to his continued dirty play and eventually to Rondo's injury. Players have to be punished for dirty plays before things get worse. By your definition, it's like saying we shouldn't punish small crimes because there are too many of them, just wait until someone commits grand larceny or murder first.
The small crimes analogy doesnt work, because (among other reasons) players on both sides of the game want it to be played with as much contact as it is, while in a crime, only 1 side will see the benefit.
If you really think Paul brushing heads with his opposition was a "dirty play", then our views on what constitutes "dirty" and what constitutes "competition" are probably too far removed from each other to really see eye to eye. I've played sports my whole life and gotten in peoples faces hundreds of times. I don't think anyone has ever once considered me a "dirty player".
I dont think Wade or Paul are dirty players (or weak in any way). I see them both (and Rondo, kg, etc) as fierce competitors, who give 100% mentally and physically, and see each game as a battle. God forbid another Marquis Daniels situation happens, but I wouldn't change how the games have been played for anything.