3 years ago our first you tube channel was closed with the same action. A generic email and this message that the account is suspened. We asked them a couple of time why, I mean everybody has the right to learn his flaws. But no answer. We have later analyzed the videos. FInaly we added the source where we licensed the pictures and music and the same videos are stilll up with another account.
So I think everyone have to learn to name his sources for third party content. Like music, text effects, testvideos and so forth.
By the way, Vimeo is not better. We tried to move to Vimeo. But what they did was to ask us 3 times in 12 months to update our account to an higher level. After we refused the third time, our account got deleted there.