Past that, psychedelics are (kaleidoscopic, funhouse) mirrors. In the hands of a curious and humble person they can (in addition to being a lot of fun shared with like-minded others) be valuable therapeutic tools for approaching firmly rooted hangups, attitudes, etc. In the hands of someone like your friend, you get what you observed.
Both are commonly occurring patterns, and if you know a person's character even a little well you can usually predict how they'll engage with and come out of the experience.
To quote Shulgin,
> The most compelling insight of that day was that this awesome recall had been brought about by a fraction of a gram of a white solid, but that in no way whatsoever could it be argued that these memories had been contained within the white solid. Everything I had recognized came from the depths of my memory and my psyche.
But I never felt like I was getting at some deeper meaning, and it wasn't something I wanted to keep doing throughout my life.
Anecdotally, I had a friend once who was very into psilocybin for its mind-expanding properties. He certainly thought he was enlightened and loved to brag about the great understanding he'd gained from his trips, but he was one of the more selfish and un-curious people I've ever known. It seems to me that these drugs create a feeling of having accessed great knowledge, but the "knowledge" is just whatever nonsense your brain conjures up on the fly, like a dream world that makes sense while you're asleep but whose logic falls apart the moment you wake up.