Instant love. I can accept that videos might get removed from YT for whatever reason, but if there's an empty spot in my playlist I want to know what it is so I can go and look for it elsewhere. Didn't realize this information was still available, never thought to look. Excellent work.
titles can't be copyrighted so that's definitely not why. I can't really guess their purpose. It might sorta make sense for 'embarrassing personal fail' videos that end up being something you wish you hadn't put online at age 14 but I suspect it has more to do with YT's 'LOL FU2' ethos.
I'm guessing there's technically the chance that a title might be problematic too, like if it contained private information or illegal speech. Although in that case, I wonder why they don't nuke the information completely.