It is still an opinion, until convicted in a court of law. There is still that "Presumed innocent until proven guilty in a court of law." A legal protection that you enjoy, and any erosion of it's protections for an alleged criminal is an equal erosion of your protection....
its not exactly hard to figure out that someone is breaking the law if they are running out of a store with a bunch of crap under their arms.
criminally undue harm? thats ridiculous. if you think its okay to go and rob a store maybe you deserve to get hit.
and its really not hard to restrain people.
Please don't come and visit my community - you might hurt someone. If we have bought a broken widget from the hardware store, we will return it to the cashier, who we probably know. Go to the shelf at the back with more widgets, and walk out the door with the new widget in the pocket - waving a cheery goodbye to our friend at the cash. If you only saw the 2nd part of what we were doing, then it sounds like you would feel justified to tackle one of us to prevent a crime from happening. Which in this case would simply be criminal assault.
And yes, it can be difficult to restrain someone. In the scenario above, I would be fearful for my life - 'cause this madman has decided to attack me for no good reason - and while your intention might be to restrain me, my intention would be to hurt you enough to stop your attack. And I would have adrenaline on my side.
I like my community..... it's humane and peaceful. We have crime, of course. In fact we had a bank robbery once. Would have totally gotten away with it, except he decided to spend a marked $50 at the video store where his friend worked. The clerk told his friend to "wait right there" while he called the cops. The bank robber waited. He got busted.