Thats an unfair assesment, though there is valid room for criticism here.
First off to be clear, they labeled certain **groups** as violent extremists, they did not label anti-fascists and anti-racists collectively as extremist and violent.
I also find it misleading that the screenshot presented **intentionally** left off the one part of the page where they go out of their way, and even put it in bold, to indicate that not all people who use those symbols are violent.
Every single entity on the internet is under surveillance. I doubt **all** servers with those symbols are under any **more** surveillance than any other. Some are, the ones who are more violent I'm sure, and no one can deny there are violent ones, I mean hell we have seen calls to violence from servers before that has caused a lot of discussion... but simply for having the symbol, probably not.
That reminds me of a scene in The Fabulous Furry Freak Brothers comics.
Since assuming that their phone line was tapped was the safest option, they made sure it was. One of the brothers mentions several inflammatory words e.g. 'bomb' and possibly yelled down the phone line.