I've marched in support of BLM. Protest is necessary, and for it to be effective it generally has to make folks uncomfortable on some level and that may include a level of civil disobedience. It's not supposed to be all fun and sunshine, particularly if you are the adversary of those protesting.
I'm diametrically opposed to Trump and his supporters on a lot of issues, but I recognize that a functional society needs to accept their right to protest as well. They should be able to have their marches just like we have ours.
However, the stated goals and actions of many of those in last week's march and rioting are explicitly violent and seditious. Many of the protestors were heavily armed. They killed a policeman.
Do you really want a bunch of very angry people to
effectively be pushed into a corner, demonized by
society and so on?
I understand what you're saying: by pushing individuals into a corner, we may make them more desperate and feed into the overall "persecution" complex that motivates their movement as a whole. I think that's true.
On the other side of things, if we do nothing we legitimize their extremist views? Those extremist views become the new normal, or at least most the goalposts for the range of views considered normal.
Admittedly, it's a "damned if you do, damned if you don't situation."
But this isn't about denying their views or their right to protest. It's about targeting specific criminal actions that we don't want my side, their side, or any side to do.