And TKD is not a good comparison to... anything. He was.. an idiot. In combat sports, you want to be STRONG. If you're competing, you find a weight class that suits you, if there is no weight class, you would benefit far more from being strong than being weak and fast. But... TKD is a point sport. He was probably meaning the Olympic version of TKD, there is no real damage built into strikes in that, it's all about point fighting. In point fighting, you want to be quick, because you're not shooting to hurt someone, you're shooting to play tag. (I HATE Olympic TKD. Combat TKD all the way)
If you're trying to cut someone's head off with a sword, you need to be able to cleave it the hell off. You need body strength, and that usually equates to muscles. These guys didn't play "tag, you're it" with swords, they fought to the death.
Also, notice in most MMA forums, people don't like the lighter weight classes. That's because they like to see bulky men fight. Guys they KNOW will kick their ass. They don't like to see lighter guys fight, the average person doesn't want to see guys smaller than them that could cripple them. They are under the impression that size = ability.
They hunt, they forage. They eat. And you don't lose 10-20 pounds of muscle because you go hungry, you stay built up, you may lose 5 pounds at most that year, but they ate enough that they didn't lose that weight.
I don't see any of them having a body builder physique. They all are rather small. Andy Whitfield was 5'7-5'9 and 158. Liam is a wee bit taller, roughly same weight. That is in no way body builder physique. The only one that has anywhere near close to a body builder physique is Gannicus, and he's still rather small.
These men have a typical combat sport body.