doesn't it piss you off when natural lie about being natural ?
no. only if drug users lie about being natural.
but actually it's not really important enough to care about if other people use or not. you have to care about your own health and longevity. if, on contest day, someone else is better, then be it - it's not the end of the world. with every contest prep you improve your muscle quality, learn more about your body etc.
if you do it for health, it's the greatest sport on earth.