It's amazing how naive is the sound of T&Cs of those sites. Something like ...it's the owner's responsibility to ensure that there are no TMs within domain name... and ...we keep the right to take down domains from the list if they "whatever"... - meaning if legal team of a legal owner comes after us.
In other words, they're absolutely happy to let them go through until they get threatened or take to the court. Just one judge's call for the records of all TM related sales and how much those sites had benefited from them, and here is another thing that makes the news for one day and gets featured on WW's home page.
Why just not being proactive and have everybody's life easier right up front?
Just like Google AdWords maintains TMs in their system, those could have the list of the words that automatically get blocked. Such solutions are so cheap. That's just an hour of coding or so, and bit more of testing. $500 the most!