You can report for anything.

When you use negative attitude or verbal abuse, anything's on the table. No, seriously. Give it a shot.

Gather up a couple friends and go into a game. Pick out a solo player on your team. Doesn't matter who, they can even be with a duo. Just choose a person.

Curse, blame, flame, do whatever. Be silent even. AFK farm top. Doesn't particularly matter. Just don't say anything in all chat.

At the end of the game, with you and your friends, act like the other person/two people were being toxic the entire game and ask the enemy team to report them with you while reporting them for Verbal Abuse or Negative Attitude yourself. Make sure you file the reports before them.

Have fun getting those lovely alerts that you've punished a player. They'll look great on your desktop when you screen-cap them.

Point is: this system is probably the most garbage-y, flawed, ass-backwards and inept behavior system out of all online multiplayer games. Bar none.