No one is arguing against preventing people in wheelchairs from getting hit by a car. All of us can, and will, do that.
What is wrong, usually illegal, usually stupid, and potentially very dangerous to society, is for you to try to act like a cop, pretend to be an interfering superhero, potentially, and eventually, making a bad situation much worse because you are not trained nor authorized nor armed to protect yourself in any except the most casual circumstance.
You are not a police officer, you are not given any permissions nor sanctions by our society to behave like a police officer, you have no authority, no training, no backup, and you are defenseless in any but the most harmless situation. It is only a matter of time before you make a huge and bloody mess for our trained police and our doctors and nurses to handle.