Lemmy was released as an open-source fediverse alternative to Reddit.
Just over a year after launch, r/ChapoTrapHouse, moved across after being banned from Reddit. This is likely what you're referring to. It had well over 100,000 active users on Reddit, so represented a sudden sizable influx of users.
I'd wager the biggest influx of people by far, though, occurred when Spez upset a majority of mods and many users by banning third party apps.
People looked for an alternative, and Lemmy was it.
But why are so many people who lean left politically? Because the Venn Diagram for "people who like the idea of a decentralised platform that supports everybody and is free from the machinations of millionaires", and "people who would like society that supports everybody and is free from the machinations of millionaires" is nearly a circle.
Lemmy definitely has a super majority of people who are politically left. Lemmy also has a very large amount of extremely politically left people. I am not sure why this is the case.
However, not every Lemmy user is politically left.
People have a wide variety of opinions and interests that are not represented well on a two dimensional left right spectrum.
Lemmy has a fair few people who will fight you over their own perceived interests.
Because Lemmy is so small it's common for the same people to argue over their interests in every community. In the morning I catch up on the all feed in 20ish minutes (I block politics and memes).
Take that together if you say something against any groups zeitgeist or one of their trigger topics it feels like all of Lemmy is dog piling you.
Remember online isn't the same as real life, express yourself and share your earnest ideas and don't care about downvotes. If someone is being unreasonable just ignore/block them.
Yes and no? The humans, probably. The accounts created to keep tabs on the leftist humans? Maybe not…?
Just kidding, NO conservative or government groups have EVER silently infiltrated ANY leftist groups, and me suggesting any account here is a propaganda bot or whatever is TOTALLY outrageous!
Post anything you want here, it’ll NEVER get screenshotted & linked back to you or your job in some giant hack in 5 years 🥳🤩😎
I don't know that I'd describe Blue MAGA as left of anything, since they're an pro-market authoritarian movement, but whatever they are, they're either a majority or a VERY vocal minority.