I highly suspect at least the spamming of distorted/vandalized pictures of Merkel is the work of German alt-rights (or, to be accurate, neo-Nazis).

Spamming swastikas, though, this one is a known modus operandi of trolls worldwide.

It says "rules: no swastikas", which is just an invitation for people to draw swastikas.

This reference is better than a swastika though. http://i.imgur.com/sFwteao.png

I added that after someone got snippy at me after I deleted their 'art'. This way expectations are clear about when I'll intercede with my admin powers.