What do you call an avatar that attacks an evil on sight? Or a follower of Purity? Then ask yourself what the difference is from a neutral attacking an intruder to their city on sight?
The bottom line is really this:
Mahn-Tor is hardly a lawful city. Minotaurs are not prone to be lawful. Also, there are no plans to allow minotaurs to be lawful.
I would consider that evil as well, considering I'm not religious, but at least they have some sort of greater cause, whereas minotaurs do not. In my mind a good person is one that strives to make the world a better place, and in a chaotic goods mind, i can see how slaying evil would make sense. That is hardly comparable to a minotaur attacking everyone they see on sight, with no consideration or prior motive. And Definitely no greater cause.
example: if i were to roll a neutral chaotic in D&D and run around slaughtering people for no reason, or just because they walked into the "room", I would most likely be punished, or killed off for such actions.
However if i took the same character and killed/attacked people who pissed me off, or were blatantly stopping a goal that i had set. It would be looked at as good roleplay.
All I'm saying is that the minotaurs in mahn tor act as evils, therefore if they are the apitimy of what is minotaur, then minotaurs should be evil, not neutral.