Strange is a word that doesn't mean very much. (My grandfather uses it a lot: for him, any food that's not obviously salty or sweet is simply "strange.")
There are few things in culture that are natural or fundamental. Except for brief periods of "cultural purification" such as the Akhnaten period in Ancient Egypt and 20th century Western modernism, civilizations seem to have a tendency towards more complex artistic forms that will appear strange and arbitrary to an observer who doesn't understand the context.
For example, I can't follow Japanese Noh theatre, but it's not inherently any more "difficult" than some piece in London's West End -- both require a huge amount of cultural background to be understood.
There are few things in culture that are natural or fundamental. Except for brief periods of "cultural purification" such as the Akhnaten period in Ancient Egypt and 20th century Western modernism, civilizations seem to have a tendency towards more complex artistic forms that will appear strange and arbitrary to an observer who doesn't understand the context.
For example, I can't follow Japanese Noh theatre, but it's not inherently any more "difficult" than some piece in London's West End -- both require a huge amount of cultural background to be understood.