Facebook is my major source of news these days - it's certainly how I found out about Michael Jackson's death. Everyone is posting things, some of them commenting on his less-than-stellar aspects. Many people seem to think there is something bad about that.
But, you know, I'm reading 1984. And not just reading it, but teaching it, so I have to pay close attention and explain how the system in the novel works. One of the three main pillars is the mutability of the past.
Michael Jackson made some good music. Then he possibly molested a lot of children and did some very odd things to his appearance. Ignoring that aspect of him isn't polite, in my opinion, so much as it disrespects him by immediately trying to rewrite the past to be more favourable upon his death.
Criticism of public figures upon or after their death doesn't strike me as a negative. Far worse is to be silent about the bad things of the past, as that results in their continuation in the future.