Why do people want to entertain the error that there is a ladder of progression in evolution? It is not so. In evolution there is no progress in any line at all. In evolution there is also no drive to complexity. This is all very evident in the exceptional preservation of the soft parts of fossils found in the Burgess Shale. Evolution produces endless variety.
So, what is your question? Why do people have false ideas about evolution? Likely because of their lack of an education....it is a simple as that, but I suspect you already knew this, right???
If you intended to ask a different question, then I'd suggest you ask it, rather than complain that people are ignorant...which of course, they are.
Then that brings one to the next thought:...... is why ARE they so ignorant? And that is because in general our public school systems are poor. And they are poor because they aren't funded properly. And they are not funded properly because the power in our legislature take money from education to do other things.
In this oligarchy, we call the USA, (we no longer have a democracy... the people no longer run this country...... the rich rule.) They buy legislatures to support their enterprises. And automatically that leaves out capable students, who are not wealthy. The wealthy send their children to private schools, not public ones. And the wealthy can as well fund a college education for these kids....at the rate of on average $54K for four years. Most middle class families, what there are left of them, can't afford this.
And how do the poor kids do? They don't. They go out into the world, with whatever they could learn in a public hs, and do the best they can. And our economy proves that.
Wish to be utterly disgusted at the way we educated kids and how money is distributed in this country??????
Go to Youtube, and plug in, "Wealth inequity in America". 1% owns 40% of the GDP of this country. It hasn't been like this since the days of the robber barons in the 1890. At one time, the wealthy paid 90% of their income in taxes. If you make....and many do.....$20M/year, that still leaves you almost $2m. If you can't have a nice life at $2m/year, there is something radically wrong.
Get the distribution of money in a fairer situation, and you won't be able to ask such a question....because all kids will know already that evolution goes in all directions, and is constantly in force.