When Asians use the term, we usually use it to loosely mean "my home cuisine and other cuisines that share similar characteristics"

When my wife or I say "I feel like eating something Asian today" it usually means spicy-Chinese adjacent, i.e. served hot, vegetables fully cooked, heavy on flavor, paired with either rice or freshly made noodles.

Korean qualifies, Sichuan food qualifies, Thai food qualifies, Indian food maybe sort of borderline qualifies on some days but only if we haven't eaten it recently.

We don't usually mean Japanese food when we say that. That's just our mutual understanding of what we call "Asian food". Yeah, I guess we unapologetically kicked Japan out of culinary Asia :) It doesn't matter. The system works for us. We don't dislike Japanese food, but we'll say "Japanese food" when we feel like having Japanese food.

Another Asian family from a different part of Asia probably uses the term to refer to a different subset of Asian cuisines.

Like just about everything else in Asia, it's a fluid term that means different things to different people. I've only ever seen people in the west be pendantic about terms like this. I also think of it as a very western ideology to want to have a term have a singular global definition.

We rarely say "Asian food" - we would be more specific.