Is it considered violent to slap people?

Oh shut the fck up

Yes, don't do it.  

YES it's an assault but only if used against someone who has not harmed you 3 feet space around a person is generally considered Personal Space in an argument or NON violent conflict closer than that is considered dangerous during them and some people know closer will trigger a fight or flight response and most people will fight...

N.Shadows 

It is considered battery, and you could go to jail.

When they say some people need sense slapped back into them, sometimes it's alright in a literal sense. ONLY sometimes.

I see it as doing them a favor. Some people need it.