Probably because what this poster seems to be implying is a sort of inconvenient or unpopular truth. The kinds of things that there's no point actually saying out loud no matter how true they are, because they just make people angry and being explicit about it just paints a sort of target on you instead of actually driving anything towards a solution

We already have a lot of studies and statistics about problems with education, but the narrative about education problems seem to focus on the wrong things, things that the studies and statistics don't really support.