I think people reporting it just overstated the news that feature development will be stopped in saying it's dead. Mozilla's plan seems consistent.

Back-pedal on what? Both the original leaked email and the official blog post said that Mozilla would "adapt the Thunderbird release and governance model in a way that allows both ongoing security and stability maintenance..."

It was TechCrunch who somehow translated that into "So, that's it for Thunderbird." :/

You're right "back-pedal" was not the correct wording. More like address how it was received.