Spiritual doesn't mean religious, is my opinion.

It means being grounded in something firm, whether that's inner strength or a reliance on an external deity.

Religion is not required for psychedelics, but a strong grounding in something is, in my opinion.

People have bad trips because there's something inside them that they haven't identified or dealt with properly. Anxiety and/or depression will ALWAYS flare up during your trip. It's best to deal with those properly (meaning change things in your life, not just medication) beforehand.

The article mentions that the "pranksterish" groups who took psychedelics weathered it just fine. They didn't have an expectation to disappoint. Irreverence seems to be just as good

It does sound like the opposite a bit, it sounds like attempting to create a spiritual practice, or assign spiritual significance at all was what did him in

"Atheists are mentally incapable of handing psychedelics" is certainly a take.

No, it isn't. What's important is "set", and "setting".

Set is your mental mindset. Setting is where you're tripping. If you're mentally in a good place, and you're comfortable in your surroundings, you will probably have a good trip.

If you're dealing with some shit mentally and you're not comfortable where you're tripping you'll probably have a really bad trip.

Good crutch for the weak. I've tripped plenty of times; I'm an atheist; it was great. Next time you trip, you should reflect on your need for "spirituality" and what it says about whatever is going on or not going on between your ears. One of the most amazing things about humans is their imagination and ability to convince themselves of almost anything. In my opinion, one of the points of doing psychedelics is to recapture your own imagination and flush out all the BS that other people have put in there to capture your mind. And here you are telling people to pour more programming back in there in the form of "spirituality."

It's important to not do drugs that will fuck up your brain

Not in the slightest. Telling yourself “this is a drug that is altering my perceptions and it will end” is enough for me. That’s all the grounding LSD and mushrooms require and I’ve never had a bad trip, but I have plenty of drug experience so perhaps I’m just used to being in an altered state.

Psychedelics don’t reveal anything profound, they just alter your thinking and perception temporarily.

What? No you don't.

This kind of talk is how you get tech Bros paying 10 grand for some rando to be a "shaman" during a "retreat"

It's quite the opposite. When a drug trip conflicts with one's "spiritual practice" is exactly when you have a problem. That seems to be McKenna's problem in this case: he tried to assigning meaning to an experience he had while compromising his brain function with chemicals.

All you really need is to understand that there's no magic involved here. If you deliberately compromise your brain function, you're going to have strange experiences. It doesn't "mean" anything except that you compromised your brain function.