I don't think he's speaking against the use of molly/MDMA, even though it has long term side effects people will see a lot of in the near future. But often times when molly is rapped about, it's never based on a solid thought process. I highly doubt someone whose most quotable line is "popped a molly, I'm sweatin" would have anything intelligent to say in that particular mindstate. It waters down party songs, and hip hop in general. And anyone who disagrees is delusional.