Of course, the same could be said for driving a car, having children, and a lot of other things that can make life better. Research and education are the proper responses to such risks and dangers, not banning the activity for everyone.
(not trying to invalidate your argument at all, btw. and I am not saying that LSD is the only way or the best way it could happen. But it's the way how it did happen.)
If I killed myself today, not a whole lot of people would know why. They might attribute it to something they knew about, but very, very few people know about the thing that makes me want to kill myself.
So what I'm saying is maybe you're right - I certainly have no idea why your friend killed himself, but maybe it could have been something that was devouring his mind that he kept covered up.
What do we lose by not hearing your answer? What might we gain?
Your call, of course.