+1 from me as well. It may sound surprising, but an email received is your own property and no permission is required to share it, unless you are under an NDA.
One thing is the legal dimension, another thing is the moral one. About the latter one can be of different minds. I found publication of the email in the first place shameful. If it and the whole debate that followed once it had unfolded should have been allowed to stay online is a different matter.