To be fair, the science section of the ACT is testing the ability to understand graphs and read short passages on scientific topics. In this sense, it is more of a reading comprehension section than a science section. In my opinion, this is more fair than testing specific science topics that a student might not have been taught in their high school.
My memory on the test itself may be a bit hazy (~24 years ago) and my interpretation at that age may not have been accurate, but I do seem to recall some amount of reasoning was required. E.g., looking at a graph and drawing a conclusion from it. Not any great feat of reasoning, but still one that the school faculty felt was beyond the reach of their students.
