The broad-strokes story is:

* DHH said some things on his blog that some people believe to be deeply racist / fascist (not going to unpack whether they were or not because answering that question is irrelevant to the fact pattern; consult other threads for that debate).

* A Ruby conference run by Ruby Central was asked to deplatform him. Since he's the creator of Rails, they declined.

* In response to their decision, a major sponsor (Sidekiq) pulled out of supporting the conference and Ruby Central in general, to the tune of $250k a year.

* This created a "blood in the water" situation where Shopify hit Ruby Central with an ultimatum: they would back-fill the lost sponsorship for oversight control of Ruby Central (and the gem repository they maintain, rubygems.org). And if Ruby Central didn't take the deal, Shopify was going to pull their funding also, leaving them in dire straits (this, BTW, is a fairly common corporate tactic when multiple partners share support of a service that doesn't independently generate revenue. Look for it in your own business, startup company, and nonprofit dealings!).

* Shopify now de-facto controls rubygems.org and people immediately started backing towards the exits because corporate takeover tends to be a harbinger of enshittification. As if to prove the point, Shopify's folks immediately ham-fisted the access controls, yanking several gem creators from the admin roles of the gems they created. They claim this was a mistake; several in the community do not want to give them a benefit of the doubt they are not believed to have earned.

* Community members are standing up gem.coop as an alternative gem repository.