Agreed.
The hostility is in making significant changes to behaviors people have come to depend on and not letting them no about it till later on. Not hostile would have been an email to one of the many list altering us users of this upcoming change. Not hostile would be explaining the rationale instead of just saying that the change has been already, take it up with someone else. In no way are the release notes the best place to alert users of these kind of significant changes. This isn't a new feature, or some bug.