Tell me if I am wrong, but I think if someone wants to surrender and the other players don't allow it, then there is nothing anyone can do about the player who wanted to surrender dragging things to a standstill.
Yeah for that reason I only use accepting of surrenders in team games. Because in other games the players just tend to boot anyways if their surrender isn't accepted.
What can be done about this. I would like to blacklist him from me playing more games with him.
If the player was exceptionally toxic or used offensive language, you can report them by clicking their name from the player tab and using the Report button.
You can add someone to your block and/or friend list from their profile. This will stop the player from joining games that you create.