Barkley wasn't that dirty, he was rough on offence, but he admitted to not put much effort on defence. His quote was:
"Yeah Ernie, its called defence, I mean I wouldn't know anything about it personally but I've heard about it through the grapevine."
I also recalled back in his playing days with the Suns, someone asked him why did he not get that many fouls despite his rough style of play, and his response was that you pick up fouls by playing defence and he doesn't play much of it.
The Barkley teams have pretty much always been average to one of the worst defensive teams in the league during his Philly and Phoenix days. His DBPM has been average at best, and his DWS is no where close to defensive players like the Admiral, Hakeem, Eaton, or Pippen. Barkley CAN play good defence if he wanted to, but he saved most of his energy on offence, he is sort of like T-Mac in that regard.