I came around a while back on Leftists using "lib"/"liberal" as a pejorative, because I once thought it was a needless demarcation. Liberal thought posits that an optimal society comes from individual rights, freedom of thought and tolerance. Leftism, as a result of roots in Marxism, trades tolerance for intolerance as a necessity to maintain the first two requirements of an optimal society. Leftism/Progressivism argues that those who'd threaten the first two ought to be removed entirely. This overlap makes them sound similar but the 3rd point is especially contentious and really came into force around 2015. The reason why intolerance doesn't contradict the first two is because society is an agreement between all members within it, and those who don't wish to honour the agreement should not be seen as apart of society. It might almost sound fair and moral if they didn't decide what could and could not be considered moral or a restriction of thought.
I think Reddit is a decent demonstration of how a handful of radicals proliferated their ideas with a few "smart sounding but not really" maxims that had idiots and midwits follow along like cattle.
Liberals were somewhat the baseline for left-wing people prior to BLM and Trump, and might still very well be the case offline, but university-educated inductees with positions of power, or those with far too much time on their hands, helped foster a mindset that very quickly proliferated into politically correct extremism.
The whole "paradox of intolerance" shite early on acted as a soft introduction to a possible scenario for redditors where forcibly removing certain voices from society might be beneficial, providing an argument for instances where free speech should have limits. Combine it with the "If there's 9 Nazis sitting at a table and you join them, there's now 10 Nazis" - old German saying (It's fucking made up.) you're positioning people who defend the rights of Nazis to speak as being Nazis themselves, really forcing people to pick a side. Combine it with the eventual mass labelling of Trump as a Nazi/Fascist, you can imagine the rest: everyone who supports/tolerates Trump is a Nazi. So, becoming a Leftist, you've now altered your mindset into believing half the country are Nazis, even conversing with them makes you one of them, and tolerating their opinions is enabling a slow decline towards tyranny. You can see how Daskins leans on the middle point especially in his videos. It really is all to dehumanise and divorce the other half of any country as being those who are in violation of society's compact.
"How to Radicalize a Normie" by Daskins is aimed specifically at "libs" to radicalise them Leftward. It also pushes the idea that the YouTube algorithm bolsters right-wing content so by finding the video you've now been "enlightened" and thus capable of being "saved" by embracing progressive values like him. They push this idea because being the "underdog" is effectively a requirement of their ideology to function. This is because in Marxism those at the top of society shape it to benefit themselves and their purposes, so if they were at the top, they would in fact be contributing to the oppression of everyone else and should thusly kill themselves. Oppression/tyranny is also a requirement of Marxist ideology to function, which is why a lot of the vague shit (internalised racism, systemic oppression, gender wage gap, patriarchy) has roots in marxist-inspired thought: it was a way to invent new ways of being oppressed you weren't even aware of or could even tell you were experiencing. They even invented entirely new sexes (transexuals) and races (Latinx) just to prolong and extend the list of the bourgeoisie's victims.
It's the reason why faggots like Hasan don't view themselves as being hypocrites when it comes to their obscene wealth because the bourgeoisie are those who specifically own the means of production, which he doesn't, ergo not in contradiction to his ideals.