Having become a critical thinker despite a childhood steeped in leftist doctrine, I know for a fact that it is possible to become aware of the left’s agenda, rather than just being a blind and deaf follower. The key to that, I think, is to introduce seeds of doubt. Challenge beliefs. I did not read that screed, but I bet there is plenty of material in there to challenge.
The left loves to call Trump a dictator and/or compare him to Hitler. The challenge is to get the indoctrinated leftist to list some of the things dictators do, and ask for evidence that Trump has done any of those things. I doubt the leftist will catch on right away to the things the American left political class does that fit right into dictatorial behavior (like spying on political opponents, smearing their character, levying false charges of wrongdoing against them, etc.)
Anyway, I realize that there is a ton of stuff that I could say on this topic, but that would make this post 10,000 words. The bottom line is that nothing you say or do will immediately open them up to rational thought, but throwing little crumbs here and there might get them to start moving in that direction. For instance, you might point out that the FBI and CIA do not hold opinions on Trump, but that any criticism of Trump came from their heads who were Obama political appointees and therefore were in those positions to implement Socialism, which Trump opposes.
Then you were kept at the kiddie table while your legs were too long for it. You had to hold your tongue while idiots were rewarded for toeing the line. You can SEE when others don’t know they’re being led by an invisible nose ring. Welcome to my world.