This textbook is from 1929 and was probably being written at the exact same time as the Snopes monkey trial (1925). You're reading science hype because science was under attack; and not from "social justice warriors" but from conservative Americans. Notice that the single most transformative discovery in all of biology, evolution, isn't mentioned.
That attack on evolution is still taking place. In Texas there was an attempt to strike all references to evolution and climate change from the curriculum, along with other attempts to introduce biblical references. When did that take place? That was this year; oh, and in 2023: https://www.wsj.com/us-news/education/texas-education-board-...
Getting mad at "social justice warriors" for an imagined reaction while ignoring the actual attacks on science is... well, it's what I've come to expect.