17 year olds think this because the schools teach them as such. They taught us the idealized version of communism, without any of the negatives. It wasn't until some random jackoffs on the internet pointed me in the right direction when I was a teenager in the early 00's, but only after I had already made myself look publicly stupid by regurgitating what I was taught in high school. When you leave the American high-school classroom lesson about communism, not knowing ANYTHING else, you leave wondering why everyone isn't doing it.