Inconclusive
Nothing about the Blackpill taps into "High IQ" knowledge, the hardest topics to grasp is some Biological knowledge. Blackpill is mostly noticing basic patterns and trends and regurgitating it in different forms, hence the basis for most of the Must Read Threads. Many of the Must Read threads are simply multiple studies compiled and regurgitated in different manners. It's not like users are trying to make detailed threads about Operating Systems or Umbral Calculus, which is quite difficult to do even if you were to regurgitate it in different forms because you have to understand it thoroughly first.
That's why I think it's inconclusive, you can't tell if the user is "High IQ" for making a good post because whatever learning barrier the Blackpill needs, doesn't need High IQ grasp it. You could say that they are creative, but creativity is only a small subset of someone's IQ, therefore we don't have enough information to say whether someone is High IQ or not based off that.
This is besides the point, but if GeckoBus isn't LARPing, his IQ of 90s isn't that low, you can still make lengthy detailed essays with it on various topics.