To counteract the toxicity of some players, Valve has been working on a new system that will automatically mute abusive players.
In their new system, if a player has been reported for abusing the voice communication feature, they will first receive a feedback warning. Should these players ignore the warning and continue with their abusive behavior, they will be automatically muted to all players by default. To remove the penalty, players should earn enough XP by playing more games. The mute, however, isn’t permanent. Other players may choose to unmute them while in-game.
To report players abusing their mics, choose the “Abusive Voice Chat” option under the report menu. To counteract troll reporters, Valve is adopting a weighted reporting system. Players who play more or report less frequently will have more impact than people with no XP and report often.
Valve has not yet set a timeline for their new system, but we do expect it to be live in the next updates. You can read more about the new mute system here.