Maybe he lacks taste buds, biologically?

I'd say 90% of places I went were remarkably meh. But that 10% was on point.

People go to italy or france, eat at some shitty place, says it's overrated.

Or maybe they aren't used to non processed food?

Well I've never been to Finland, maybe their food is vastly superior. And to be fair it doesn't take much to be better than the USA. So maybe your friend is right