Thanks for the research, it's true this could be a loophole, but it's actually a little more complicated than that. Did you actually get word from YT they would leave your videos alone? 'Putting something in their face' is actually quite hard. YT is notoriously difficult to contact, even when you're perfectly in your right.
YouTube also removes videos where users may contend that it was just fair use they made of a clip. Users have been suspended, just because they used a commercial clip for comic effect in a much longer video, because they used clips of a video game they reviewed, because of some copyrighted background music they used, because they were singing a copyrighted song etc. Yes, even Dutch YT singing star Esmee Denters (20 million viewers, I should know ) was thrown off for a while, because music lawyers realized she was covering a lot of songs, and that was like millions of radio plays without any royalties getting paid! It's all a matter how you interpret the DMCA (Digital Millennium Copyright Act).
It's very murky, and YT can remove videos relentlessly and indiscriminately, just depending on some automated crawler/upload filter or the threat of getting sued for millions by the big moguls, like Fox, Viacom, Warners etc.
Work your way through this thread, if you like :
There's another article:
You may get lucky, but don't count on it. YT officially only allows video and audio that is completely your own creation, however untenable and ridiculous this may sound. It's why I'm no longer on YT, because most of the clips I uploaded, favourited, shared with friends or commented on (mostly not our own work, I have to admit) would be gone after a while.