"His contribution to society is really not that significant."
Define significant. Did the Mona Lisa solve world peace, discover electricity? No, but it was significant, from both a cultural and artistic viewpoint. The human condition drives us to find heroes, those who we feel deserved to be revered, Michael was someone who deserved this hype.
Michael's dance and music was, and is significant, there was something about it that attracted and mesmerized millions of people. Don't belittle him. I assure you he has accomplished more than you ever will.