Any such topic would benefit greatly from adding the age of the children we talk about, because I feel many people talk about different topics and have misunderstandings because of that.

There is absolutely absolutely zero, nil reason to hit a small children (let’s say, below 8-10?), as they simply won’t understand the consequences and you are just assaulting the poor thing without any benefit. This is simply unforgivable and should be grounds to take away said child from the parents (depending on the degree), or press assault charges to non-parents.

What seems to be more commonly acceptable (and reason for disagreement) is a spank/slap for older children (e.g. teenagers), which is quite common in certain cultures. I’m not sure on the research on that, but it should be qualified because one is imo an absolutely evil view point, while I personally don’t agree with the second, it is at least open to discussion.