Shout cooldown
There is a lot of spammers. Instead of muting them (and possibly losing sales/trade messages from them), I believe a solution is a 30sec (or whatever) cooldown on shout chat. This should also help to stop Argentinians raging at each other 24/7 (I am also Argentinian and honestly it's annoying AF).
Either that or a trade channel with a different colour that u can mute would be helpfull aswell :)