While I am inclined to agree with the spirit of your post, it is slightly too simplistic. Children can be reasoned with only to a certain extent, depending on their age; anything beyond their capacity of comprehension can be asserted with authority only, until they grow old enough to understand. In fact, not even 20-year-olds have fully developed brains, and interactions with 20-year-olds and 30-year-olds are generally different—although this has nothing to do with parenting.

Regarding child-beating, you are correct, but it is worth nothing that there are people who take this to the extreme and call even the smallest physical contact abuse (much the same way some extreme feminists call virtually everything rape).

Good post!