There are more people who needs indefinite bans
You'll realize that if you just play some under lv30 games and see the amount of toxic "smurf"s who constantly flame their teammates(which are legitemately new players) while taunt with every word they can when they beat up enemy new players. Most of them are silver/bronze players who got their main account permanently banned for toxic or other reasons.
This is not the first time I talk about it and I don't think I'm the only once noticed, I don't know why Riot haven't done anything specificly about this, they try pretty hard attracting new players but they just stand there and watch those toxic "smurf"s scare new players away.