The world isn't so black and white. Even in the US, the home of free speech, you can't post child pornogaphy online. You could easily put forward the argument then that freedom of expression doesn't exist in the US.

Freedom of expression has never really meant you're completely free to say and anything (at least no in a civilized world). There are always going to be gray areas, but equally there are areas where expression should obviously be protected.

An example would be, if Facebook decided to eradicate all homosexual content. Clearly the EU stepping in and saying you can't discriminate against gay speech is protecting the gay communities freedom of expression.

Equally the EU stepping in and saying the Facebook isn't doing enough to protect victims of revenge porn is providing safety online. And is a reasonable balance between the rights of free expression from the poster vs the victim.