This is why we can't have nice things you just assume he's not going to comply but you don't even make an attempt to resolve the issue in a gentlemanly fashion.
Why? Because you can't be bothered to
Yes, because it's a waste of time and resources.
One developer, one email conversation, fine, not the largest time investment.
What about all of the other developers in the world?
Especially if this became a recognised method of gaining work?
Suddenly you need full-time staff dedicated to the non-core-business activity of writing "gentlemanly" emails.
It's unworkable.