It is a sad but simple fact: Yahoo! doesn't give a damn about board abuse. It doesn't matter whether it's flagrant racism, vile misogyny, filthy obscenity or even death threats. I've reported countless posts, and Yahoo's response was to make it more difficult to report abuse. In the rare instance that they delete a profile, it's like playing Whack-A-Mole; the same user pops up with three new identities.
The only thing holding this board together is the individual consciences of its members. And the great majority of the "regular" members have none. They are mostly sociopaths. They'd stab their own grandmothers so they could laugh at the funny faces she makes while writhing around in her death throes. They don't care about other people. They don't care about the promise they made to NOT behave as they do when they joined Yahoo! All they care about is the ego boost they get from seeing their vomit in print on the World Wide Web. And if they can hurt or offend someone in the process, it just makes them feel even more important.
Reporting them doesn't work. They can't be reasoned with, as they lack reason or conscience. You either choose to play in their $hit-filled litterbox or you go away.
It's not right. It's not fair. It's not legal. But it's how it is. It takes a legal flyswatter the size of Time-Warner's to get Yahoo's attention.
I agree with everything you said... and it won't accomplish squat. You can't force these folks to behave as they promised to (that's why we label them "sociopaths"), and Yahoo! won't.