Those are all valid questions, and concerns. I wouldn't personally attribute them all, if any, directly to immigration, but willing to consider each point and think about them.
What I would say is, if you're someone who just wants to have a grown up conversation about the immigrations levels in this country and what we can do tackle the issues you're raising here, going along to a riot where they are attacking black and brown people, burning police stations, attacking mosques, looting shops and setting fire to police cars and local property is not the best idea, because their agenda and your stated agenda would not be the same.
If I had grievances about how black women are treated in our hospitals (which is a real problem by the way), and I wanted to protest that, I'd be an idiot to team up with local criminals who just want loot, riot and destroy property.