Riot doesn't care about the report system
You could tell people you kill themselves and not get reported. You could AFK in base and spend the whole time typing out some sick, erotic My Little Pony fanfiction and not get banned. Honestly, you won't get banned on here unless you call someone gay or black.
"5/21 Top Thresh? Nah, let's not ban him.
AFK Pantheon? Nah, let's not ban him.
Lissandra called you a f*gg01? Thanks for submitting your report. This player will receive a punishment immediately. Thanks for making League a better place!"
Honestly, there was one game where I got the usual pentakill, and my black friend said, "My n1**a," in amazement. That's all he said, and he got suspended for two weeks because of that.
Like honestly, Riot, it's 2017. Trump got elected because literally most of us are sick and tired of this garbage.