In most cases, I would agree with you. However, I went through a bad time after returning from overseas; I got angry a lot. I rationalized it in my head, but it was all irrational. I got so angry at points that yes, I wanted to hit my wife; but I managed to keep control. And it wasn't just my wife; it was the guy in that car who cut me off (I could have taken his head off); it was that yokel in the check-out line (would have been real easy to just beat the tar out of him); etc., etc. I got some counseling, and worked through it. Things are better.
The point being, while I managed to maintain control and fix it, I can understand others who might not, and haven't. When you get so angry that you just "lose it," it doesn't matter whether it's the wife, or the neighbor, or the kid down the street; it doesn't matter if you're 5'5" or 6'7". And afterwards, you just sit back in confusion, wondering how it was possible that you were so far gone.
So again, in most cases, I would agree; but not all. Such things need to be fully investigated to see if it's a case of cowardice, or something else.
Please don't take this as trying to make an excuse for those that beat their wives; this was a response to a particular comment, not the situation in general. I will always fall back to my response on the first page, just after the opening post.