I think as a society we fetishize liberalism (by which I mean "democracy and human rights"; "liberal" as a synonym for "left-wing" is a distinctly American usage) so much that we've forgotten what it is.
We like to think of liberalism as something so wonderful and enlightened that we discovered it through superior moral force, but in reality, liberalism began as a truce. "I won't use government to impose my religion or culture, and in exchange neither will any of you." It's no coincidence that the first liberal government, that of the United States, began in a country without a clear ethnic or religious majority (with hindsight, we can say that "white Christian" was the majority, but the different white ethnic groups and Christian groups didn't see themselves as the same or like themselves very much at that time).
The reason I say this is that, ironically, the people most eager to oppose liberalism are the people who benefit most from liberalism. The opponents of liberalism are generally people with extremist political views or from minority religious groups - precisely the kind of small groups that majorities actively try to subjugate or suppress in illiberal regimes.
Let's imagine Tumblr gets together, takes over the White House, and starts guillotining homophobes and billionaires. Do you really think conservatives won't use this as a justification for lynching everyone with dyed hair? Or that centrists, normal left-wingers and other people who don't care about politics but don't like political violence won't condone or even join in with this behaviour? Furthermore, conservatives are a much larger and more powerful constituency than Tumblr Leftists; this bloodbath will be very quick and one-sided.
Or on the other side - imagine Evangelicals trying to turn America into a theocracy, Handmaid's Tale style. The opposition coalition would include everyone who isn't a fundamentalist Protestant - the secular far-right (such as most Neo-Nazi groups), the far-left, the regular left, centrists, otherwise-apolitical people who don't want to live in Jesusland, and their usual political allies, Roman Catholics and Mormons, who Evangelicals typically see as heretics. And the aftermath would turn "Evangelical" into a cuss word for decades to come.
Basically, The Revolution would be worst for the people who want it most, and I think if we stopped thinking about liberalism as a self-evidently good utopian system and started thinking about it as a clever political bargain more people would get this.
