NOTE: This is purely speculative and I'm not very confident about it. I doubt there is an answer to this topic, and I'm sure my reasoning is as flawed as any other, but I wanted to argue something different for shits n giggles.
So it seems that J types (especially ExxJs) are considered the most dominant/aggressive. I can see how that makes sense, as Te and Fe are often thought to be domineering in some way, and very determined and goal-oriented, blah blah. But let me consider a few other types...
Domination:
I think it would be fair to say that Te (and to a lesser extent, Fe) types are the ones who most wish to be dominant, as manipulation of external dynamics seems to come natural to them. However, I'd suggest that types like ENTP, INTP, and INTJ may in fact be far more dominant, even if they don't realize it. A society that depends so much on ideas, innovation, and technology is, in many ways, dominated by those who develop the things/ideas that future generations run on. I'd wager that the inventive ENTP can have a far greater mark on the world -- and one that lasts long after they die -- than a power-hungry ExTJ, who may be too focused on short-term goals (money, accolades, career) to do anything with long-term impact.
Aggression:
Are ExxJs really the most aggressive? Indeed they are driven toward goals, but imo it's those same goals that make them less aggressive than ExxPs. See, an EJ has to carefully weigh their actions to ensure they reach their goal, so they may only be as aggressive as their situation allows. An ETJ will be hesitant if the logic clearly calls for it, or to maintain order, as will an EFJ if it's necessary to maintain harmony and/or relationships. However, the EP sees little reason to hold back; after all, their main function is to simply experience the world for what it is. They have little concern for failure, unlike the EJ. They are less likely to care what others think, or how an action fits situationally. They just want to take it all in, and imo this is most conducive to aggressive behavior.
So, why not ENTP?