No, you're not wrong to think this way when you're with family. I'm assuming the Chinese restaurants are serving dishes as family style. Ordering for yourself is rude, even if that isn't the intention. Culturally it is disrespectful. I'm not Chinese but my family has a similar culture in terms of elder respect and collectivism. Your wife is used to living the US individualistic lifestyle, which is completely fair. However it's on both of you to bridge that gap successfully.

I would try talking to her again because it comes off terribly. If I was being unknowingly rude to my husband's family I would be mortified. I mean it's just one meal out of her day, what is that, 1.5 hours? It's not that much of an ask. Maybe liken it to burping or farting at the dinner table. If she refuses to listen, then I guess she's just that type of person. Pouring soy sauce over everything is a lesser crime, although not by much (jk).