@Wyrm Presumably because it's obvious what the girls want to do. The girls understand the importance of the oracle and though may not want to go with this hero, in this world they may be otherwise dutybound to follow it. Suimei is basically giving them an out. When the Hero asked the girl if she understood the importance of the oracle you could see the clear hesitation of speaking her mind here. Look at how Suimei gets reacted towards when he "defies" an oracle. It's just deep rooted into their culture, such that neither of these girls are able to pull out quite like Suimei can.
As for Suimei
also not asking what the girls want to do as if falling into some kind of
typical of men behavior, I think that notion is beyond silly. Does he really need to ask them for their opinion on the matter when it's written all over their faces in order to cross his T's and dot his I's in the whole "woman respecting" department? It's obvious from any angle they want nothing to do with this hero and even if they went with him, it's because of external pressures. That's like a mugger walking up to you and your wife, demanding you hand her over, and you quipping "Honey, now I care about your opinion too. Do you want to go with the nice man behind that dumpster over there?" before you proceed to shove his own knife into his throat or can we just cut out the obvious questions entirely?
Honestly at this point, I understand he thinks he can just kick the shit out of this hero and be on his way, but it is a bit dumb he can't just break out of his cloak and dagger bullshit for a moment and explain his own provenance as a means of getting away from this situation. One of these girls
is the girl who summoned him. It could have even further gone into a "even still you're not a hero, I'm taking them anyway" direction and we can still watch Suimei literally wipe the floor with his face, but he should at least be willing to defuse a tense situation.