On iOS, yes, it has a built-in browser. You can go to Safari if you like.
They're not packaging up web content as if it's not web content, though. It's just to access sites quickly.
And I've gotta say, I'm really bothered by the way Facebook handles browsing. I have to copy the link, exit Facebook, open Safari, then paste and navigate to the link whenever I want to have a page I found on a Facebook post in my bookmarks, reading list, etc. Super frustrating.
If I open a link in Facebook, tap "Share", I see "Share in New Post", "Send in Messenger", "Copy Link", "Open in Safari", and "Save Link".