If you recognise the urge and haven't followed through, I assume you wouldn't call it "morally acceptable", but it really sounded like you were agreeing with that position originally.

A “good idea” is not a bad impulse, it's a good idea.

If that’s what you meant to say, you’re extremely bad at expressing it. After all, you wrote this:

... if you've never thought that spanking a child might be a good idea then you don't have kids. Those little shits don't understand empathy or anything else that you're appealing to when you say violence is never the answer.

That’s exactly the opposite of the comment you were replying to. You’re not saying that parents sometimes get angry, but that they consider violence to be a solution. That’s not the same thing!