An FPS shouldn't have this much CC

Wrong.
Its not like overwatch’s stuns.

You can do not get outright denied from playing the game if you get stunned by the concussions. You can STILL outplay the characters who DO use them against you.
But thats up to you and your skill.

meanwhile in this game. you get denied essentially by every other character.

Im excluding mei from this because her “stun” still leaves room for counterability.