I'm not sure how anyone familiar with open-source communities would fail to predict the backlash though. They really should have forked the repository and switched the deployments over to their downstream fork (if I'm right about the root cause here).
(I'm mostly thinking in terms of supply-chain attacks, like this one: https://blog.rubygems.org/2025/08/25/rubygems-security-respo...)
In other words: that argument is interesting, but it feels strained to me :-) -- I don't think RubyGems or Ruby Central is actually legally liable in this way (or if they are, it suggests a failure of clarity in their EULA/TOS).
The (mostly PR) explanation they produced seems to express roughly the same thing I was guessing though: https://rubycentral.org/news/strengthening-the-stewardship-o...