Umm, which countries are you talking about here? I've been to several countries and I really don't think I've been anywhere where it's "completely normal" for men to have visible abs (let's say for definition's sake, I don't think I've been to a country in which >10% of the adult male population has abs). Not that I could necessarily tell most of the time, most people have shirts on during the day.

I do agree with your point though - I don't think visible as are unhealthy.

They are very much malnourished and their body fat percentage is lower than is optimal for good health and they most likely suffer from the associated complications of too little body fat.