Oh and the best question is:

How do you even know anything said by the user holds any spec of truth whatsoever? No one on IRC is under oath and is free to lie (or joke) as they choose.

Meaning, if you actually are going to try to chase after an anonymous user over a disturbing discussion, you should have some concrete proof besides the actual log, since the log doesn't really mean much even if you _could_ prove that it wasn't edited or forged.