1). assuming both have same amount of fat, the small guy of the same weight has less bone mass and therefore more muscle mass.
No. Bone density and thickness rises in proportion to load put on it. A 110kg guy is putting a greater load on his bones just walking around than would a 70kg guy. Bone density and thickness also rise in response to resistance training. It's possible to have a 70kg guy with denser, thicker and overall greater mass of bone tissue than a 110kg guy.
The muscle mass will be in proportion to the bone mass; all the things that build up or knock down muscle also build up or knock down bones, and vice versa.
Torque = Force X arc length... Taller guys have longer arms therefore, they're doing a pull up/ chin up of a longer arc distance than shorter guys. So more Torque required.
Or more precisely, greater force to achieve the same torque - that is, greater force must be exerted to get the weight (or person) from A to B. That's why weightlifting favours people with relatively shorter arms and legs.
Still, the larger guy will tend to have more muscle mass, and will thus be able to produce more force than the smaller guy.
Overall, strength does not rise linearly with size. The 110kg guy can't necessarily lift 110/70 = 157% of the smaller guy's lifts. But he should be embarrassed if he can only lift 25% more, or the same.
Morgan is just trying to make excuses for himself
It'd be like me trying to justify why I'm not as strong as Shorty up in Queensland, doing his 200+kg deadlifts at under 70kg. I'm not as strong because I haven't trained as hard and as long as him, not because I'm taller.
