It seems to me that they are occupying a sort of hybrid space. They say they're not broadcasters. They say they're just the platform and they're not responsible for any of the content, yet they do seem to feel that they have some responsibility, because they are taking steps. People may feel the steps are inadequate, but they are taking some steps to provide greater transparency.
Why are they doing that? I think it's because they know they can't quite get away with just ignoring this entire issue. They do bear some responsibility in a broader sense, if not in a particular legal sense in any particular jurisdiction. Whether they would have stronger responsibilities if particular jurisdictions, either on an individual basis or on a global basis, decided to say, “No, no, you really are broadcasters and you have to start acting like it”, that is a question for legislators, not regulators.