I get what Scazz is saying with his.
They aren't using /All to talk, so the enemy team doesn't know what is being said. They are talking only to their premade team of 5.
Scazz is saying the enemy shouldn't be able to report for toxic chat since they never said anything that the other team saw.
Best way I can try and display it:
Draven:[All] Welcome to the League of Dravvvvveeeen!
Jax: [All] Glhf
(misc talking in team chat)
Draven: Jax why'd you take my kill you no good skill lacking bastard?
Jax: Not my fault my lamp post is better than your axes you psycho.
Draven: I'm not playing Jinx you blind potato.
(more random team talk)
(Jax and Draven win)
Draven: [All] Thanks for playing. Better luck next time in the League of Draven!
Jax: [All] Gg.
So the other team never saw the 5 premade messing with each other or saying anything in /All. But the losing side has a particularity salty player and decides to report them for negativity. Jax and Draven both get flagged because of the team chat that the salty player never saw. The salty player wasn't affected nor did they even see the chat so Scazz is asking why should the system punish them when the player reporting wasn't effected?
(Doesn't effect me since I use comms when in premade and we verbally jest instead.)
Now granted Scazz actually means on the larger scale of people doing /mute all at the start and then reporting post game without seeing anything.
I guess an analogy would be hearing a wreck/accident behind you, turning around and then claiming you saw what happened to give a statement.
It is a reasonable question, especially since if someone was toxic, another who saw and was effected would probably report anyways.
At the risk of it being a tasteless question; Why would you ask a blind person what colors a painting has?