It's not "fears" about copyright infringement, it's just the way things are. You, as the creator of a work, have the right to control where and how it is published and copied. It is illegal to post private correspondence publicly without the permission of the author.
EDIT: There are, of course...
No, you should not, unless you have received explicit permission from Dave to do so. In addition to the ethical concerns, the emails he wrote are copyrighted material that you do not have the right to publish.
This is a common misconception, but it's not actually true. The way it works is that the network incentivizes adding more computational power by rewarding the computer that extends the chain, and dynamically adjusts the difficulty of extending the chain to roughly match the amount of power...