I throw people (the ones with good ukemi) in a manner that some people would call 'violent'. But it's just way to much fun to send your uke flying through the air, rolling and standing up with a big smile on their face. And doing the flying part yourself is even better.
In real life the effects would indeed be devastating, but on the other hand, a half throw might just not work.
And in the case of a joint lock: tapping means releasing uke.
I don't like people trainig violently with me, but those people who are too nice are as annoying as the violent ones, although they are less dangerous.
Coming to think of it, I don't train with the real world in mind. So my level of violence is to have fun while searching for effective technique.
As mentioned by other in other threads: for me self-defence is the last real world benefit I expect to get out of aikido. (By which I don't mean aikido is not effictive as self-defence.)