Nevertheless, the overall point stands. Someone still wrote a "very ugly" email about Cruz (which is probably an apt-description, else it wouldn't have been a big deal), and the repercussions of that email are what caused the problem.
I don't see how that is the fault of the Cruz campaign given that they obviously didn't know about the email until someone on the Board itself gave it to them.
“...the repercussions of that email are what caused the problem.”
The email was private. We all say things in private we don’t want made public.
The one who leaked it is the problem. The email was nobody’s business except the one who mailed it and the one to whom it was mailed, least of all the Cruz campaign.