The person in the article who apparently viewed it multiple times over a long period of time absolutely did so deliberately.
I think the point in sending you the image was to show that, in general, it is possible for images to be present on your computer without you actively attempting to access them. Not to say that the argument was valid in this particular case.
I thought pedophiles looking at CSAM were more likely to attack a child, not less. They are actively fantasizing about it, and that can escalate.
I am basing this belief on what I remember of discussions regarding that "ask a rapist" reddit megathread. Apparently psychologists thought that was horrifying.