I have seen popular Facebook Pages with millions of followers like Eric's Creamy Memes, Meme Supreme, Wholesome Memes, Lean Mean Saucy Memes, Dankland, that post images that don't belong to public domain.
Some of the images even have a Shutterstock watermark on them - like this one.
The same can be said for hundreds of such FB/Twitter/Instagram accounts
Why don't they get any copyright strikes? Why doesn't Facebook takes these posts/pages down?