I'm one who had two screamers. My son thankfully is very happy in the car so who knows how long he will stay RF. He is also smaller.
My first screamed so bad that quite often we just didn't go. People would actually get really angry at us for turning down an invite that was over an hour away. They were like, "That's dumb babies sleep in the car, I never heard of a baby crying in a car...."
That wasn't fun to deal with. We were like, too bad so sad we are staying home. It was always something dumb and unnecessary. We saw them all the time as it was. I wasn't going to put my baby and myself through that for no good reason. They even got mad when we didn't want to drive 5 hours away. No thank you. My first screamed so much before we put her forward facing. She was also big for her age so that helped.
I am certainly not ignorant about bad things happening as you can see from my sig. I know it can happen to me, it has and I have no desire for it to again.
Since it has I have heard of worse too that make me think no car seat is safe. (FYI my daughter didn't die in the car, I'd rather not talk about details really) Anyway, a lady my DH works with had her kids both buckled in their seat belts and the car started to roll down the hill while she went around to get in. Both children died. That wasn't even very fast at all, and they were properly restrained. It can happen anytime, anywhere despite your best efforts. They weren't even on the road yet, so, so, so sad.
On the rear facing thing, it seems like it would smash the car seat into the back of the seat then drop it back down. I know some seats have a bar over the top for that but mine doesn't. Maybe there is a video of why it is safer RF, maybe it will make me feel better.