This was set up a few months before the infamous 2016 Leslie Jones Twitter Meltdown, which made the frontpage of Time Magazine, led to Milo being banned, and would be described as Jim later as the "shitposter holocaust" as that's when the infamous shadowbans/throttles began to be rolled out en masse (which is when people would really start to look at alternatives). https://encyclopediadramatica.online/Fembusters/Leslie_Jones%27_Twitter_Meltdown
You can ask @Moon about the early history of GS, but much of the original community of the fedi of statusnet were "white techbros", foss nerds, and similar back when they'd be at the ground floor of anything truly new.
I did not come from Twitter but I set up my server roughly coinciding with being annoyed that some places like Twitter were banning people. Not because of any specific reason but just that, I wanted a "social media" I could enjoy and not be subject to someone else's whims on what I could post. I believe that sealion.club and freezepeach.xyz were set up specifically in response to Twitter bannings but I was not involved with that.
@jeff@Moon@kirby I think the problem is that like history of something like SomethingAwful or imageboards, due to a lack of or broken archives, people changing over time and/or leaving the fedi, and instances going down for some reason or another, it's a very much oral history.
There's also the fact that the fediverse is split into several groups, so someone who will know about the legend of Bot and 🔧, NAFO, Wyatt's hellthread, or all the lore of graf won't know about something like snouts.online folding (and scaring furries away from Mastodon for a while), or all the sex pests in the Mastodon side, etc.
@jeff@Moon@kirby The problem is, with fedi history the boomer theory of "two people in the same theater watching different movies" applies.
The Mastodon Network (tm) side will say defederating gets the bad people offline and cite Gab. Ask someone on this side of the fedi who was there and they'll just post the YOUR WHOLE FUCKING MENTALITY HAS EXPIRED video or the screencap of Gab users crying about anime spam.
There's also the baggage that the Mastodon Network branding carries, but that's another story.
@PurpCat@kirby those two servers definitely courted people banned from Twitter. I attempted to try pump.io (the thing Evan P one of the authors of ActivityPub made that almost killed the network) before my GNU Social server. I was and am very interested in freedom and decentralization which was my primary motivation. SPC started as a strong free speech instance that basically banned violent threats, doxing and loli, sealion didn't. SPC has since created more rules on perceived and real harassment. we absorbed a lot of users early on from another shitposting server named gnutan.xyz that went defunct after a database crash. I'll try to add more facts as I remember them.