Like a moment that seemed insignificant and unimportant at the time, but looking back was in fact a pivotal moment in pushing you towards radicalization.
For me probably being introduced to Guitar Hero at my friend's house in like summer 2007. At the time it was just another day, but looking back I ended up falling in love with those games, I ended up being introduced to The Ramones and even more importantly the Dead Kennedys through them, which caused me to get into punk music and resulted in me adopting very critical attitudes towards larger American society, attitudes which later grew into anarchism and then Marxism
I don't know what instance you're talking about, about hexbear is probably the most active explicitly left-wing instance in the lemmyverse. There is hexbear.net/c/askchapo or hexbear.net/c/lib_rehab if you want to ask a bit more spicy questions. Or pick any other comm that semi-fits what you want, it doesn't matter too much.
hexbear.net/c/theory is probably where you want to go if you want to read more theory and there is also
https://bulletins.hexbear.net/posts/readinglist/
There probably are also very valuable comms on lemmygrad.ml but I don't know about that instance too well unfortunately.