Without getting too much into this, there's a difference between taunting and psychological warfare and just being a pathetic person.
There is a line to be drawn, and I'm sure Riot is aware of that line. for example, there is nothing strategic in someone saying "stfu you f noob, your mom is..." and similar
I spent 3 years in actual combat and even when you interrogate someone that doesn't yield results, it's just plain blunt.
Question: if I report someone for whatever, do they at least get a warning?
I'd hate to be the cause of an unjustified ban, if someone was having a bad day or just lost their temper one game, but are good team players usually.