The trolls have gotten VERY sophisticated and it can be very difficult to know the difference, especially when they go out and put up convincing flyers then take photos of them and set up online groups, just like a real organization might do.
they started the rumor to stir up xenophobia. They started the campaign in July 2016. You can even read them discussing starting the Facebook group you found. It’s designed to convince you and many people.
What’s scary about these folks is that they know *just* how to make some things spread.
In 2016, I remember they were putting up fake Twitter profiles with stereotypical looking feminist profiles with pictures of badly drawn Nazi hate graffiti (that they did themselves).
The left believed it and it made the news.
The right who *weren’t* part of the planning thought it was faked by the left because it was so obviously badly done and those who sat in the background that got the controversy started just monitor what happens and laugh.