Hey there. I've edited your post to remove the pictures you had included. I know you meant well, but naming and shaming other players isn't something we allow on the boards, regardless of them being guilty or not. You're allowed to provide pictures for as long as you edit out the player's name(s).
Threatening to ruin the game for other players could potentially warrant punishment, and actually doing it definitely does. That being said, if you do go through with the game without dodging, you can report them using the after-game report system, and be sure to include a note saying which chat this took place in. Riot is able to view logs from pre-game chat as well as after-game chat. If you were unable to do so, you can also submit a ticket directly to Riot Support.
If you have any questions or concerns regarding this moderator action, please visit us in the Moderation Discord Server. If you'd like to leave us feedback on our moderation or the boards in general, please make a thread in the "Discuss The Boards" sub-board.