Tanks.

"Consider that not everyone wants to play AT."

So, you admit it is a choice, that there are options to deal with it (many of them actually), and you are choosing to make yourself weak to it.

Off the top of my head, things that can take out a tank:

1. RPGs (any class can pick up).
2. Engineers Starting Launcher (which also applies a mobility debuff).
3. C4 (any class can pick up).
4. Other launcher that can drop (forgot the name, any class can pick up).
5. Recon Drone self-destruct.
6. Recon Drone bomb drop.
7. AT Mines (any class can pick up)
8. Acoustic Mine (any class can pick up)
9. Repair Torch
10. Any player getting within interaction distance of the tank (any class can do this).
11. Airstrikes (any class can pick up)
12. Artillery (any class can pick up)
13. Anti-vehicle Grenades (any class can pick up)
14. HE Grenade Launcher against very low health tank

I'm sure I missed some. Maybe try learning how to properly play AT (I suggest large map conquest) and you will see that tanks are pretty much driving coffins to someone that knows what they are doing, unless that tank has proper infantry support (repairs and people watching for attacks from all angles).

FYI, mines get more and more dangerous as the circle closes down, because there is less and less room for the tank to manuever.