I shot an ak with a SVD stock instead of a pistol grip semi-auto and I could handle the recoil no problem and im about 5'6 & 140 lbs. I am sure that I was firing 7.62x39 ammo. PS I have very little experience with firearms.
Don't know why either....my 15 year old son is 5'4 and can take the recoil just fine....in fact he likes to bump fire it, and still take the recoil......They might not be complaining just stating the difference between an AK and an AR....I know that I have shot an AR-15 after shooting my AK and it felt like shooting a BB gun after the AK....but that being said...the AK doesn't really kick much...