I wonder if you would feel different after witnessing an execution (by guillotine)? I believe Camus is arguing that you would, giving his father as example of someone who similarly changed his mind.
Anyway, there are a great many videos online of murders and other death scenes, and famously there were VHS tapes available pre-internet called "faces of death" showing such events. A great many people actively seek out and watch such things, seemingly with no negative reaction to them. So there are a lot of people who would presumably be even less affected by a guillotine execution than I was.