Riots system of reporting is ridiculous. "toxic" is so broad and safe space nonsense
If you are crushing in a game, your bot lane is feeding and refusing to ward or group or do anything they should be doing and you get frustrated and tell them to "fucking group you idiots". This isn't toxic, this is a competitive person who wants to win and people who refuse to work as a team to do so.
If they talk back and you and get into an argument, this is not toxic. This is a stupid internet fight that means nothing and the team can mute them and you if it bothers them.
NOW, if a team member is intentionally not grouping or INT'ing THAT is toxic. That is what should be bannable. If a person is using racial slurs and other nonsense, go ahead and perma ban them.
I'm sick of pinging assist 20 seconds in advance only to watch my team not react or someone doesn't want to work with the team because "he didn't get ganks and you are a shit jungler" and I'm supposed to just sit there for the 10th time that game when asking nicely does nothing and just suck it up. Has anyone at riot ever played sports? it seems they haven't because if a player on a team did what these kids do in ranked, they would get yelled at and benched.
I'm sorry but calling someone bad for playing bad or telling them to play safe and stop fighting is not being toxic, its being competitive and RIOT has normal and ranked games confused for some reason\
Also if you are "playing ranked just to mess around and have fun" stop. ranked is for winning and competing. Do that shit in normals