Kyle Richards -- Dog Trainer Says Sister Kim Is Unfit Pit Bull Owner

Kyle Richard's sister Kim is an unfit dog owner and her pit bull should be taken away from her immediately ... so says the guy who tried to train the dog and almost got a piece taken out of him.

David Utter says Kim ignored both his warnings and the warnings of Bravo producers from "Real Housewives of Beverly Hills" ... warnings that the pit bull should be muzzled at all times.

David says Kim played with fire ... allowing Kingsley to run free around the house without any restraint ... putting guests in great peril.

The trainer is indignant that 3 people were bite victims ... all inside Kim's house. And David says the 3 strikes law should apply here.

He's not advocating that Kingsley be destroyed, but he thinks the dog should be immediately taken away from Kim. Thing is ... the Dept. of Animal Services will only get involved if Kyle's family complains about the most recent attack against her daughter ... and that's unlikely.