He was not uninvited. He was simply asked to share the keynote with other people. Not an unreasonable request given how large the Rails community is.

> because he had "mostly been offline for the past year"

While poorly worded and not accurate (I assume they refer to him not engaging on Twitter or perhaps lack of communication with the Railsconf-people, but yeah he has clearly been online) this is not the reason for him being asked to share the keynote. The email says the committee has made the decision while him being offline, there is no reasoning given for it beyond just having more people doing the keynote than him.