To be fair that was a comment left on the BBC website and not "news" from the BBC, but it should have been more carefully moderated.
People are always quick to jump to conclusions until the actual answers are found, see Amy Winehouse, half the comments at the time were "no surprise really, always knew she would overdose eventually" - until the post mortem proved otherwise.
It is possible for people who have been drug users to not die from their drug use, but from something entirely unrelated. Shocking, I know, but perfectly possible.
Better to sit back, say nothing and wait until cause of death is established before passing judgement, if you feel the need to pass judgement at all. What really matters is that a child lost her mother, her mother lost a daughter, and the world has lost one of the most amazingly talented singers it has ever known. Surely that is what is important right now.