Taking the broader view, I wonder how much complaining about cheats is really an attempt by Goliath to have slings declared unfair.

Reminds me of the Playing to Win essay linked here a few weeks ago.

And how much of the desire to be nice and conform is evolution telling David to fall in line.

That doesn't make sense, though. If playing "cheap" in this way benefits David against Goliath, then evolution would favor a whole lot of Davids playing "cheap".