The chart says about hallucinogen users: "Continuing to take the drug, they become insistent that everyone else use it also."
I doubt that's any truer for hallucinogens than for other drug types. Sure, back in the sixties you had Timothy Leary and various musicians openly advocating LSD, but it's not as if there's anything inherent in psychedelics that "makes" users preach about it. Any more than the late Peter Tosh and various "marijuana" political parties around the globe are evidence that cannabis "makes" people do that. There's sometimes peer pressure within groups of friends, sure, but that's true of any substance. (If I had a dollar for every time some of my grad school friends said, "Besamim, you're not drinking! Besamim, have another drink...")