Yeah, you're right. We all have an axe to grind against 4chan. We're all making up that we saw CP on it.
I'm a former Goon. I've been all over the trashy parts of the internet. It doesn't benefit me whatsoever to lie about seeing CP on 4chan. I even remember exactly what the picture I saw the last time I went to it looked like. It is seared into my memory. That was my last visit to that trash site.