They were responding to the comment where "9AM EST" was explicitly used. I don't understand the value of your comment as it doesn't serve to clarify - I think most if not all readers would understand the reference.

Yeah, I saw that but I figured both people would see the response if I put it on the child comment since people often only look at comment replies and their children. Conceptually I was replying to both.

There's an hour difference between "9am est" and "9am edt".

I understand, but that was not the point of my comment.

To out pedantic you: the problem only involved Amazon.com not Amazon.ca ;)