Unlike bodybuilders caring about appearance, these guys only care about strength, so they don't go on cuts, its just about building muscle, so they are in a constant 'bulk' phase, which adds fat.

(that's an oversimplification, they do do some cut, particularly for weigh ins, like with boxing and wrestling you wanna be in under a certain weight to be in a particular category. But as a general rule I meant, there's more 'bulking' as compared to bodybuilding)