That's... arguable, autoteam/autojoin is a very useful and used command to make players able to join teams when stuck on spectator without needing to rejoin the server, specially in arena based gamemodes (JB, VSH), removing it would fix this glitch until someone finds another way to exploit it, but it would be annoying to new players needing to rejoin because they are stuck on spectator, making them probably ragequit and giving them a bad impression about the server, even if it's not a big problem.
I would recommend to try to fix it in another way...