LaRouche is far from a perfect analogy for Trump, if only because LaRouche had bizarre but passionate opinions on why Plato ruled but Aristotle drooled, while if you were to ask Trump for his thoughts, he'd tell you that Plato has always been his favorite Disney character, but he could tell that Aristotle was a bum from the moment he met him. But LaRouche and his followers helped build a world where Trump could thrive. A world where Alex Jones could become a celebrity and the alt-right movement could spring up, all because we accept that a certain level of violent, factually dubious ramblings will always be buzzing away in the background.
Before the advent of podcasts and YouTube videos in which people with terrible haircuts talk about how the latest mass shooting was staged or those dastardly Jews are once again oppressing the endlessly trod-upon straight white man, LaRouche's supporters would occupy street corners and invade college campuses to picket and hand out pamphlets, write their own books and magazines, broadcast radio and TV shows, and generally live in their own reality. They were the forerunners to internet conspiracy theorists and hatemongers who will say anything to get attention, and who will believe anything to feel special. Some even spent years working and living in LaRouche's offices and compounds -- while now, thanks to the magic of the internet, you can immerse yourself in an all-consuming alternate reality from the comfort of your own home.
LaRouche's most hardcore believers dedicated their lives (and often their finances) to the movement, and LaRouche turned them against their own families. If you weren't with them, you were dooming America. They heckled and harassed political opponents, actual or perceived -- they were traitors, communists, icky homosexuals.