Yeah, trolls, feeders and inters fucking suck. Millions of us have to deal with them every single day. Surprisingly, (Or not surprisingly if you're part of us) 95% of the community doesn't flame, utter slurs or yell bloody murder if this shit happens to us.
Holding your temper in isn't that hard to do, it's something you learn as you grow up. Throwing tantrums doesn't reward you or punish the wrongdoers or even accomplish anything useful. The only thing it _will_ accomplish is a fast track to getting banned.
Ultimately you are responsible for your own actions. If you get trolled or whatever just report and move on with your life. You might not realize it, but even though trolls and feeders are harder for the IFS to detect, their first punishment is always an escalated 14 day ban, the next is a perma. So yes, Riot does take trolls seriously.
TL;DR: Protect yourself, hold your temper in check, don't utter slurs or hate speech (those will get you an instant 14 day ban) and just report those bastards that think it's funny to ruin everyone's fun.
Sincerely, your friendly neighborhood never punished 95%er