What we tend to lose sight of when we focus on Mike being a vain half-wit who makes everything into a referendum about his public image is that John was not at all interested in Elly's crusade to save the town hall. This seems to be part of a wider pattern in which he makes a point of being totally disinterested in anything that makes her feel like more than a nobody doomed to go down in history as nothing more than that useless figure who might as well not have lived at all: someone's wife or someone's mother. When you listen to his whining about how her having a career destroys his home and how remodeling the kitchen just because she wanted a change is a needless expense because his mother never complained about clapped-out appliances, you end up realizing that his idea of give and take is that he takes without giving and she gives without taking.
This belief is reinforced by the fact he regards her as a poor sport for not caring about HIS stupid interests. She doesn't like model trains because she doesn't know how to have fun. She doesn't like sports cars because she wants to make him into an old fogey. She doesn't like this, that or the other thing because she doesn't seem to want to agree with something everyone knows: men get to do interesting stuff while women are fated to tend house and shut up about it. This not-needing-to-be-spoken belief of his means that the the television adaptation in which he makes an oafish comment about Elly getting back to her real job of being a housewife means that his response would be a variation on the phrase but that's different should the dichotomy be pointed out to him.
The reason for his smug belief that he's not supposed to care about outside interests that should probably be discouraged so as to preserve his home is that John has privilege blindness. Since John clearly believes that Elly's complaints about how the system is rigged against her are so much rubbish because the system works in his favor, it would take a Herculean mental effort on his behalf to see that maybe it isn't crazy woman hormones that make her want something she "shouldn't" want because she "doesn't" need it; since he's a very lazy man who doesn't like to upset apple carts any more than he likes the idea of being the bad guy, we're going to have to wait until they slam the crematorium door on him for her to be rid of his stupidity and short-sightedness.