This has been happening a lot lately, Whether i am first or second pick, Someone bans the champion i hovered on and when i ask them why tells me to stfu or something insulting of nature or sarcastic for that matter, That is more toxic than someone actually raging for not having ganks or running down mid (for me at least), As it already puts me in a bad mood, not having my main and not wanting to play with that sort of person
Griefing and tell you to "STFU" is reportable. When reporting, say it happened in Champ Select and ask for a manual review.
If the person is being a dick after doing so it is reportable. Hell, if they arent smart enough to just say "sorry, i didnt see you were picking them" and just straight up flame you they deserve the ban.
If I see you wanting to first-pick Yasuo in silver elo, and I peep your op.gg and see a 2 KDA and 40% winrate, I'm banning it. Sorry. "Main" or not, if you aren't competent with the champ, I see no reason to turn a blind eye to it and knowingly decrease my chances of winning. And that alone isn't bannable and never should be. It's a strategy game for a reason. But the taunting and bm.. Riot needs some in-lobby reporting options like screencaps and whatnot.
im sorry the whole team believes your 
mid is a bad call, especially when the enemy team has already locked in a leblanc.
but me allowing that to go through is more harmful than me banning your pick.
we tried asking you not to, you said i'll do w/e i want, its normals.
but a reliable 85% of the time your pick gets banned simply because you aren't first pick and they dont want it on the other team either. not to troll you.
Pick a wrong champ for the wrong lane and of course you're gonna be chastised.
