They're obviously doing something right.
First off, where are you getting the idea that science and progress are inherently "good," "moral," and "Libertarian" pursuits?That's pretty funny. That massive violence or racism come from attempts at progress is a good joke. The "scientific racism" that you refer so was attempts to push traditions of bigotry and hate onto progress and science. It was a perversion of science and progress. Likewise it's hilarious that you think there was anything progressive about fascist regimes. They were all about tradition and traditional authoritarian models.
They are mere tools, neither good, evil, nor liberating in and of themselves. What matters is the person making use of them, and their goal.
For that matter, some of the most horrific regimes in human history (Red China, the USSR, and the Khmer Rouge, for instance) started off with "equality" and "human liberation" as their primary goals. Hell! Even Hitler and Napoleon were reasonably "progressive," at least where social policy was concerned.
Simply put, it is not said that the "road to Hell is paved with good intentions" for nothing.
Blind faith in progress, for progress' sake alone, can, and often does, end in disaster.
Because it often is, perhaps?And why do you think that idealism is blind?