False. At 6'5" you can expect more muscle for a similar physique than 5'5". I'm exponentially stronger.
That's just simply false. Why are most bodybuilders and olympic lifters short then?
Shorter limbs provide mechanical advantages in many cases. Why can I squat and deadlift so much compared to many people taller and heavier? Partially because I am shorter and don't have to move the weight as far.
It's typically easier for shorter to people to add muscle because the muscles are shorter versus longer. Longer muscles are more spread out meaning they usually don't get as big.
Absolute strength tho is largely based on weight, however to some degree. It is true that a taller person can weigh more, but at the same time, there are more important factors to consider like muscle insertion points, leverage points and muscle type. If all things are equal, then of course the heavier person can lift more weight and would be stronger. Very rarely are all things equal however.
None of these are absolutes---of course there are 6'5" dudes who are behemoths that are absolute beasts. And there are 5'8" dudes who are scrawny. And everywhere in between.
Also keep in mind that strength is largely mitigated by leverage. Why are 6'7" or 6'8" 325 lb tackles able to be picked up and carried backwards by 6'0" 250 lb Outside Linebackers in the NFL? Because the OLB's are shorter and can get lower than the taller Lineman. The low person has all the leverage and can just use their legs to drive and the taller, heavier upright person can't do much about it other than go backwards.
The mantra in every short yardage situation in the NFL where 11 players on each side of the ball line up along the line of scrimmage and the ball gets handed off to the RB to try and pick up a half a yard ?
"Low man wins"