That said, the comparison is made, simply because there aren't any Women to compare Rousey too. In our need to classify how good Ronda Rousey is, we want to now compare her globally.
Ronda has said herself she does not want to fight men. I concur with her, it's bad for the sport, and she has nothing to gain from it.
There's been plenty of discussion about this on Sherdog and /r/mma... and even some historical precedent. I recall seeing a video awhile back of a then female undefeated kickboxing champion vs a journeyman fighter and while the female fighter showed more speed and skill, the physical advantage made the fight extremely lopsided.
It's disappointing that we'll probably never see Ronda realize her full potential because she doesn't face enough competitive pressure.
It won't be decisive. It would amount to an assassination. I'll let you figure out who would kill who.