Self-promotion is against the rules, and a lot of people perceive e-celeb threads as self-promotion. Probably with good reason, too, because a lot of people don't actually care what Pan or Furious Fernando think of anything and people who don't care about those e-celebs assume the only reason the threads exist is as promotion.
As opposed to something like Double King, which was a high-effort animation that took two years to make and produced some reaction images for people who were charmed by the main character.
I'd say it's ironic that people would rather discuss a primary subject rather than the secondary opinions of a "reviewer" or whatever, but it really isn't. If people on 4chan want to talk Digimon, they make a fucking thread about it.