The first, of course, comes from having to listen to John's retrograde bullshit about how any discontent that Elly might have in life is all due to woman hormones screwing with her head and making her not like what she's "supposed" to. Since the boy doesn't have many friends outside the home and those who are are like the Pattersaints in being smug hicks who take a sick pride in not falling for new-fangled concepts, it's sort of easy to see why he treats women as inferiors.
The second reason is sort of related to the first. Even a clod as oblivious, oafish and insensitive as Mike is can't help but notice that Elly really doesn't like to have him underfoot much. It seems to him that her whole life is one long exercise in trying to run away from him. Since he started out as a dumb kid loaded with self-pity and jealousy and simply got larger as he aged, it's sort of obvious that he can't see that it's because she's conflicted about motherhood or anything. She just wants to have a job to run away from him because she hates him.
The last seems to be his exaggerated fear of being teased about what Elly does. Like the noxious little bully he is, Mike tends to whine piteously when he is exposed to the same sort of hateful teasing he 'defends' himself with in order to defend himself against the cooing interloper who has obviously bewitched all those around her and is totally not a defenseless, inoffensive little girl being picked on by a hateful little brat who thinks the Sun shines out of his ass. Simply put, Elly has to chain herself to the stove so a thin-skinned little punk doesn't have to get teased like everyone else.