Maybe ego isn't the right word. But, IMO, interfering in a robbery is not really using common-sense in many/most cases.
To me, although there are exceptions to every rule, if someone wants to steal something and there's no real risk of physical harm in letting them do so, then I think common-sense dictates one should avoid any confrontation and let them have it. Because even when you know you'll be safe, like when you're armed, it's still potentially problematic to escalate things.
For instance, let's say I catch someone robbing my house and I confront them and wind up shooting them. First, I'm not sure robbery should be a capital offense. But less philosophically and more pragmatically, if I shoot somebody, even if I'm fully in the right, there's still a good chance I'm going to wind up having to hire a lawyer and spend tens of thousands ensuring I am cleared of any wrongdoing. And even if I know I'm not going to shoot an innocent bystander, I can't say the same for them if they are armed.
Most of the time, it's gonna be simpler, safer, and cheaper letting them get away, and just collecting insurance for whatever they took. Better to focus on noticing and remembering any details that might help apprehend them.