At least they ask founders to be not mean [0] and specifically be nice [1] but do ask them to be relentless [2] and formidable [3], which may come off as shrewd?
YC has pretty strong ethical guidelines for founders and people have been removed from YC for violating them, so I'm not sure where you're coming from with that, unless it's just a cheap shot.
[0] http://paulgraham.com/mean.html
[1] http://paulgraham.com/safe.html
[2] http://paulgraham.com/relres.html
[3] http://paulgraham.com/earnest.html