Most of it boils down to lust. They see pretty they want pretty, like King David.

Ultimately it's not needed ATM but may one day be needed.

Culture was different back then as well. If a woman was not married she was considered destitute (same today tbh), went into whoredom (look what's going on today), or sold into slavery (also look what's going on today).

A marriage to a man prevents this. He's a leader, they are not. He is leading his flock.