The fact that Michael Jackson had recorded vocals many times on certain songs does not necessarily prove that he liked these songs.
If he liked these songs, then he would have released them (in one way or another) during his lifetime.
For instance, 'Slave To The Rhythm' was one of these songs (for the posthumous 'Xscape' album).
But Michael Jackson did not like that song, considering that he did not include it on his 'Dangerous' album, or on any other later release (studio album, box set, etc) while he was still alive.