You are right, it is a myth. But you can understand how it propogates by virtue of the impression one gets from the cases reported in the media - where the matter of the abuser having been abused himself is frequently used as an item of mitigation, in my book wrongly.
so all abused do not become abusers. Some do. A lot of abusers were abused themselves.
The only reference to any figures I could find is in this video article by a PhD specialist who estimates 1/3 to 2/3 of abused go on to become abusers.
