why ban during coop (bots) game

There are still 4 other players in that game that didn't find your behavior acceptable. A better question is why did you act that way in a bot game?

just because it's a bot game doesn't mean you're allowed to be toxic

Negative things that you do in Coop/bot games do impact 4 other players in the game. If you impact their experience in a negative way, then you would be deserving of a punishment.

In a bot game, you still have four teammates that are real flesh-and-blood people. These players have just as much say in what kind of behavior they expect from the community as those playing in any other queue, so their reports have just as much weight.

Co-op vs AI is not "lack of responsibility mode", it's simply a slightly lower-stress way to learn or just play the game with other people.

Like leveling up another acct i just want the free win so why can't I play some rocket league with my friends? Why do i have to be there and partake in the bot stomp? I have had players afk on me and it just means more bots for me to kill.

Being toxic should be wrong but idk... why cant I afk in bot games? To me bots are easy and my thought is they are only used for leveling or practicing a champion. I take it others don't agree?

Honestly I'm fairly neutral on this. However, it's a bot game, you can easily just take like 10 seconds and tell them you have to go.