Had no idea what kapporot or shechitah was so I had to look them up. From what I read Shechitah is just another term for Kosher slaughtering and im going to guess your issue is with killing a chicken rather than someone giving away coins in Kapporot.
Therefore I'm assuming you are arguing that slaughter of animals for food via kosher means is materially worse that other methods. And materially worse enough that you think that attacking those people who follow that practice is rightly justifiable?
As for the circumcision of boys I actually agree with you. To me it is the genital mutilation of a minor and I believe it should be banned. One of my relatives is a neonatal nurse and she nearly had a baby die because of a botched circumcision. The rabbi hid that he had nicked an artery and kept just mopping up the blood.