It may be bullshit, but certainly not obvious bullshit. Communism is a real solution to a real problem, thousands of people fought for that. It didn't work out in the end, but if you think it is obvious then you probably didn't think about it enough.
History books? Let's look at the French Revolution, often credited with so many great things. The period following it is called "the terror", you can't get more explicit. Anyone reading just that part would want to bring back monarchy, and that's actually what happened. But anyways, for many young people, me included, history books are either stuff to memorize for the test, or something that reads like The Lord of the Rings, but with slightly less magic.
It takes some experience to actually understand what's behind history books, and considering "obvious bullshit" as you call it is the kind of experience that get people to better appreciate history books. At least the ones that are not an excuse for propaganda.
Communism was obviously bullshit to me based on just a basic knowledge of human nature. It didn't take much life experience to figure that out, and reading a few history books only confirmed what already seemed obvious. Thinking deeply about nonsense is a total waste of time; I had better things to do. The problems were real enough, but Communism has never been a solution to anything. If young people saw it as a solution then I have to assume they were just too trusting and naively believed the lies that ambitious idealogues sold them.
Because it is a fallacy to attribute to nature what is clearly at least significantly product of social relation.
This is one of the very interesting things everybody (no matter their political affiliation) can learn from Marx and the whole group around Adorno and Horkheimer, but you will find this echoed by more conservative sociologists and historians, too.
Zizek also frames this quite nicely in The Perverts Guide to Cinema, where he explains, that ideology is never a pair of glasses [EDIT]you wear[/EDIT] but the very eyes through which you see.
Right now I sadly cannot look through my books to find you less leftist references for the topic.
If you are interested I can link to some less controversial works of sociology once I have access to them again.
(Edited for some typos and the marked addition.)
