No, he assumed incompetence, which you seem to be intent on proving by continuing to attack him and give this non-apology apology.

Had you taken a few minutes to check before doing this, we'd all have been better off.

Or you could've resolved this a week ago had you had a more mature process. The guy laid out the issue, presented a fix, and e-mailed you and the rest of the Core Team several times. How many more "few minutes" does he need to take before it stops being his fault in your opinion?

Stop attacking the guy, it's really poor form. Just admit you guys screwed up and move on.