American doctors would recommend it back then. Everyone was doing it. As you know, most Christians, religious or otherwise, don't really know/follow everything in the Bible.
"Like in other 'Arabized' Arab nations, the Arab identity of Palestinians, largely based on linguistic and cultural affiliation, is independent of the existence of any actual Arabian origins."
Such precision isn't required by the religion, but it is an interesting problem. Facing Mecca for prayers from anywhere in the world and determining prayer timings were scientific problems that drove early Muslims make advancements in astronomy, cartography, etc.
You're right, many (most?) ancient civilizations knew the earth is round.
It's not a big mental leap. Things disappear over the horizon. The sun and moon are round. Maybe the earth is round too š¤