Yeah, unfortunately for everyone he was only warned on the worst of the interactions and given a second chance. Sometimes a ban on the first offense is better. Still, a ban after a failure to heed a warning seems completely reasonable. Heck, a re-evaluation of the original interaction with the knowledge of how he behaved after the warning would have worked too. But again, the important thing isn't where the ban happened, it's that the project rejected a bully.

The important thing is exactly when and why the ban happened. As others have pointed out, his latest bug report that got him banned was hugely better than his older bug report filled with personal insults that got him a warning. This shows that he took the warning seriously enough to stop the personal attacks.

Banning him now makes me think the developers of Thunderbird are ego maniacs.