Not a single one protested the violence (although that I understand : in Brussels you won't get beaten up, or worse, for excusing or even supporting terror. The opposite stance gets you branded racist in the best case).
There are numerous places in Brussels where the tension between the police and the new "locals" is very close to the flashpoint. And to be frank, Brussels is positively peaceful compared to Paris and Rotterdam. I do not have direct experience of how it is in other cities, but I doubt these cities are the only ones. Antwerp, where I live, is also rapidly becoming a flashpoint and has been the site of muslim terror attacks against Jews. Tellingly, lots of Jews are leaving.
And let's get one thing straight. Brussels is loaded to the brim with minorities. From the black community from Congo to Lebanese and Iraqi Christian refugees, all have communities. Whilst these communities aren't without problems, there is only one community that constantly commits violence on everyone surrounding them. From "youth" randomly attacking whoever is stupid enough to get on the metro alone (and I'm a man, any woman knows that you can't take the metro alone anymore. 5 years ago, not a problem). I just want to say : it's not just these attacks, in fact, that's the least of the problems.