People will see what they want see, on FB or elsewhere. They’ll download the files they want to download, they do the drugs they want to do (or find substitutes). You can inhibit that through censorship to a limited degree, but by doing so you also endanger your own free speech rights.
I’m not comparing the US and Germany, I’m pointing out that if you have to pass a law to suppress something, then clearly you still have a problem with that thing, and I would argue that force is the least effective way to deal with it. We all patted ourselves on the back for purging the Confederate flag, but here we are with Donald Trump within striking distance of the White House.
You don’t measure social progress by what you prohibit. You measure it by what you can afford to allow.