Look, people are surprised because Facebook has become an integral way to communicate with someone whether it be via chat with messenger or as a broadcast message via a newsfeed post.

Internalize this: Facebook has become as integral to communication as having a cell phone was in the last decade. If you met someone who didn't have a cell phone today (whether it be a smartphone or otherwise), wouldn't you be surprised? That's the same surprise people are giving you.

That's their perspective and it's not unreasonable.