Well that's no surprise. It's not even about games or skills.
If we're talking an online shooter with no auto-aim then it's all about which tech allows you to most quickly select a pixel and press a button.
M&K is demonstrably faster so unless you adjust the settings or use some form of auto-aim for the pad then K&M as input will defeat pad as input for such titles given equally skilled hands.
Try to be reasonable... its easier than you think...