> It is possible to use it in an unabusive manner
All the scientific data that exists says you're wrong. You can debate the quality of any particular study... but there doesn't even EXIST one in the last several decades that found anything different. 

>So the problem is abusive parenting, not corporal punishment.
No. They are two different problems. They are often correlated but it's not an either/or question. Both are problems that need to be fixed. The evidence suggests that fixing the latter will make great strides towards improving the former.