As a long time F2F player, I have never understood the problem that the email community has with forwarding email. I have always taken it just as I would someone telling me what another player is saying. The tangible artifact of the email is so easily edited that it is almost valueless.
Which, IMO, makes it a particularly poor tactic when used against good players, who will recognize it for what it is -- an attempt to gain influence that isn't based on the merit of the speaker, but on the (supposed) bad behavior of someone else.