Teams can divulge sensitive information to each other in the /all chat
There is no useful information to share in /all chat, as such there is no reason for it. I would consider this a bug as this seems to be intended for some unattained goal. It is only used for toxicity and to help the enemy team win by giving up information on your own team.
It should be permanently disabled as it is not fulfilling a useful purpose.
I understand that we can report the toxic players, and those who cheat by giving away team information but there is no reason they should even have the capability to do it especially since the method they are using seems to be designed for this exact abuse.