I think you're jumping the gun a bit with him. We know from chapter 11 that it's the common view in the country that "A young, unmarried women of a noble family working a job would be considered disgraceful" and from even earlier chapter that having no fiance after graduating is problematic. It is a misogynistic view, but it's not a him problem, it's just the common sense in that country. Still a rude person tho.
You know, technically Keios becomes the way he is because of "circumstances that led him to being (the way he is)" as we've seen from chapter 10.5.
I'm a little conflicted. On one hand, Keios is the way he is not because of malice, but because he's just a dum dum, so I can't abhor him. On the other hand, reading these "Women becoming strong and independent" always makes me think "yas girl slayy" (I know it's cringe, but it's perfect for the occasion). One that i really wanted the FMC to get away from the MMC was "What It Means To Be You". But it slowly seemed like it was heading towards reconciliation, so I dropped it.