Facebook never occupied the same role Twitter did.
Facebook was originally a place to connect with friends and share pictures/posts. It then morphed into Boomers sharing conspiracy theories with other boomers. It was contained.
Because of that, it never held the status among celebrities and politicians and the journalist gadfly set that Twitter did. They wanted to blast their opinions to the world l. Twitter was for news makers and famous people holding online court. It occupied a much pronounced role in the political and social sphere than FB ever did, especially zombie FB which is a wasteland of AI nonsense and boomers posting stupid sheet.
That's the difference.