He was the most critically acclaimed pop artist of the 1980s. I mean, in the 1980s, Michael Jackson was basically considered to be a rock god.
He had some really good songs, there's no denying that. Less so as time went on.
He could dance, he could pull moves like nobody has ever seen, that is also true... and that made him a very impressive live performer.
Michael was abused by his father, who basically forced him to be an entertainer. He became a gigantic celebrity, but he was never quite "normal", in fact he was plain weird. There's no denying that. Increasingly as he got older.
Was he a paedophile? I don't know, how could I know, BUT... it's a registered fact that he did share his bed with young boys... and that is pretty dodgy, no matter how you slice it.
In answer to your question, he's popular because he made a massive impact on modern music. Nobody who lived through the 80s would deny the significance of Michael Jackson to those times. Of course, this was BEFORE anyone suggested that he was a kiddie fiddler.