I finally had enough and moved tells to their own tab and disabled notifications.

Goldfarmers can continue spamming but I'm not listening any more. It's a shame that the only way to block this crap is to cut off all communications from all players, but in the absence of any actual effective action I'm not left with much choice, I'll just retreat into my little bubble and only communicate with FC and LS members. Way to build a community, devs.