I have been hit by flying objects thrown from vehicles. Soft drinks and milkshakes mostly. The people who do that are criminals, and I wish the police would do more about it. It's not like some hollywood comic scene where someone get a pie in the face. When you get hit by anything traveling 50 or 60 mph it's deadly, not even counting being knocked off the bike / taking a spill. But a gun isn't going to help in that situation - I agree.
I am hoping that Illinois gets a carry law soon. I guess anectdotaly - because I haven't been seriously injured I can say I haven't needed a firearm, but I've had some close calls with some very powerful dogs. In one case an older man was walking his a pit-bull type dog on one of those retracting reel type leases. And he didn't have the right kind of collar on the dog. This was on a trail - not the road but anyway the dog went after me and the lease kept reeling out and reeling out. I had to petal like mad dodge the dog, go off the bike path and then outrun the dog while the lead keep reeling out and reeling out. The dog was not having a fun chase - the dog wanted to attack me. I'm not saying that I wish I'd been able to shoot the dog. But I look back on that incident, I had to go off the path. I was in tall grass and had no idea if there was a hole, a large rock or branch - if I would have hit any of those, I would have been off my bike and the dog would have been on me.
Just my past experience with dogs has convinced me that I am going to go armed if I have the choice.