'but you're pinning the mass-murders of the 20th century on "intellectuals"?'
Intellectuals provided the impetus and moral theory for the revolutions, started the revolutions, enabled the continuation of them, and in the non-Communist countries flew active cover for them. We still have intellectuals today like Friedman who fly as much cover for murderous totalitarian regimes as they can; it hasn't even stopped. Intellectuals are yet to give up Marxism, despite what it actually does. It flatters them so, a toxic meme that can only strike the smart.
It wasn't every last person everywhere who might have called themselves an intellectual, but it sure wasn't "the common man" reading Marx and deciding to break out the pitchforks. "I am a barely literate peasant and I demand the immediate centralization of all power into the government so it can be run by the intellectual elite, create a single central bank, eliminate my religion, abolish my private property, remove my means of communication into centralized control of the state, and write glorious Five Year Plans so I can stop farming potatos!" They provided a driving force for change, but the change itself was controlled by intellectuals.
"Intellectuals" may not be solely responsible, but they weren't even remotely innocent, and it is entirely irrational to pretend that intellectual ideas not accompanied by humility and an intense effort made to discover whether those ideas are actually true before making grand pronouncements that move countries have not had massive negative impacts in our world today.
"one of our major political parties and it's major financial backers hate the policy implications of some important scientific conclusions"
I assure you Democrats are equally prone to it. If you think the Democrats have been some great boon to true science it's only because you're a Democrat yourself. As neither Republican nor Democrat, neither political party (emphasis "political") has particularly impressed me with their devotion to scientific truth. Though I will concede the Democrats have done a great deal better job pretending in the past decade, at least inasmuch as it was politically convenient.
And remember perception really matters here. You may refuse to chalk up these actions to "intellectualism" no matter what contortions you have to go through to account only good to its cause and discard the evil, but those of a "simpler, less intellectual" bent won't go through those contortions, and that's not necessarily irrational. It's no great wonder "I'm an intellectual and I'm here to give you the answer!" isn't something that makes an American drop everything to listen.
(And they have done great good, too. One Norman Borlaug can offset an awful lot. But it's not a path to an accurate picture of the intellectual history of the 20th century to take credit for Norman but dance away from, for example, Eugenics, to name just one problematic entirely-intellectual idea, and what it wrought.)