The funny thing is, they have a threshold of 100.000 users that must be registered at the site. So a site like unzensuriert.at (like breitbart in the US) which is a right leaning / government favourable website will not fall under such a law and won't get penalties.
So, will a site maintainer simply remove the older accounts that have not accessed the site in a while, to keep number of accounts below 100 000?
I'd probably keep the content but orphan it and kill the underlying user and profile.