Yes, everyone seems to have a problem with this issue, it's very annoying!! They'll only stop if a moderator says so.
I've tried to tell them to use PM'S.. They just attack back, I don't think this will go away honestly, It's been 8 months when I didnt play and I had the same issue as a Moderator.
I think it's wise to tell them to stop spamming the yell channel with a PM and if they get defensive, report it to a moderator.