This is so true. When you have a billion users, you can literally lose hundreds of millions of users and it wouldn't make a dent. The only way is to get the government involved and regulate this and just keep hammering them with massive fines that really make a dent in their bottom line.

For a lot of people, government regulation of this sort is not desirable, but at what point does someone need to drop the hammer to stop this?

As it should be. If the cost of fixing the problem is greater than the amount of harm the problem is actually causing to society, then it shouldn't be fixed. Set fine amounts accordingly. (Whether we actually do set fines this way is, of course, questionable. And probably this particular problem would get fixed even if there were no fine merely because of the reputational damage it's causing, but I'm speaking in generalities here.)