Why is it unreasonable to expect the RubySpec dev to do additional work, but reasonable to expect additional work from the MRI devs to comply with RubySpec?
I get that "the implementation is the standard" is frustrating for people who want to make an alternate implementation, but why should that obligate the original developers to accept some third party's definition of what their project should be?
They don't have to accept it. I don't have an opinion one way or another about the rubyspec being some kind of a standard. But if it exists and shows a sigsegv scenario and nobody bothered to run it before a release... that's a failure of developers. It's not even additional work.
And presumably the MRI devs would say that by coding MRI you're defining Ruby. What gives RubySpecs the authority to say they are the canonical definition of Ruby and everyone should follow it, when the people who created Ruby disagree?
If that's their attitude, then frankly there's every reason to complain about that. Defining a language by implementation is absolutely horrible practice.