The actual context of his argument was that religious indoctrination while disallowing questioning of the those teachings (particularly distressing teachings such as burning in hell for eternity), was child abuse. Not that I necessarily agree with this completely. However, usually attacks leveled at him turn into mischaracterizations of his arguments, such as your blanket claim that he considers religious upbringing to be a form of child abuse. I just tend to find that once you actually do some digging, most claims about him, or what he's said, are exaggerated, out-of-context, or distorted.
I'm very familiar with his works, and I don't disagree with them because he's attacking my religion because I'm equally as atheistic as he is. I just think he is a bit of a cock, and, honestly, a bit ignorant.
To quote from the God Delusion: "Once, in the question time after a lecture in Dublin, I was asked what I thought about the widely publicized cases of sexual abuse by Catholic priests in Ireland. I replied that, horrible as sexual abuse no doubt was, the damage was arguably less than the long-term psychological damage inflicted by bringing the child up Catholic in the first place."
Now he does go on to qualify this statement by saying someone who was fondled by a priest was more concerned about her protestant friend dying and going to hell, but it is still a pretty stupid statement to make in the first place.
It also doesn't take into account the idea that religious beliefs could actually also be beneficial to children. Why focus on hell only, when heaven must console many children whose loved ones died?
"No dear, granny isn't in heaven, we burned her in a big oven."
There are a reasonable number of people who are critical of him because we do understand what he is arguing, not because we don't.