I don't know if this has been addressed so here goes:
I completely agree with your statements that males are just to be used for reproduction. Likewise, the sole function of the female is to bear children and care for them, while the male 'spreads his seed' elsewhere. Those 'advantages' of testosterone you mentioned first allowed males to collect and hunt their own food and provide for the female while she took care of the offspring. If you think about it, the only function of all animals is to reproduce in which case the male would be the 'slave' for the female.
However, in our current times we are less preoccupied with having to hunt for our food in order to survive; we can go to the grocery store and buy our food easily. In the rise of civilizations, political systems, and economies, the males have now been able to use the testosterone that they once used doing more dangerous things (hunting, fighting other males for females, defending themselves, etc.) to do productive and innovative things like invent, design and come up with ideas, leaving the women to raise and bear children like they had always done. Males are the worker gender; they are biological slaves to females because they don't have as much input into reproduction, but the fact that they are the working gender has led them to become more productive and innovative in today's times.
Everything you said seems to make sense, I'm just pointing out further what happened as humans evolved and the role of men and women beyond the biological aspects.