I'm not convinced the authorities in those countries really object to the practices. Normally I would agree about bans pushing the activity into shadowy places

I'm not convinced the authorities in those countries really object to the practices. Normally I would agree about bans pushing the activity into shadowy places, but at least in this case it would probably limit the exposure to just the countries with the bad practices. Basically it would hopefully limit more international trade of people. From the opposite perspective, since Facebook unfortunately seems to be a common place for businesses to promote themselves, cutting off a country (with clear explanation why) would perhaps make some of its businesses put pressure on the government to enact some changes. Basically it would limit economic activities, and most individuals/businesses/governments don't want that.