We could, and did rely on the code he produced. But that doesn't mean anyone believed they could rely on him. If he had said, "You can rely on me", you might have an argument. Your bad for reading too much into it.
From the blog post:
> For Capistrano, I will continue to follow the mailing list, and might appear in the #capistrano irc channel from time to time, but I am no longer the maintainer of these projects.
He kind of came out and said it.
Sorry to jump on the beatdown bandwagon, but there really is no defense for your attitude here.
Setting up the website, writing docs, writing the mailing list, taking improvements -- you might not have made an explicit promise to be immortal and support capistrano and all western civilization in perpetuity, but your actions led people to believe they could rely on you.