Furthermore, communism isn't what most people in the US think of as communism.
When you say "socialism" or "communism" to most Americans, they think "Soviet Russia, Maoist China, North Korea".
By and large, those countries were not so much socialist as totalitarian—and it's the totalitarianism and the drive to maintain it that caused the problems and the terrible abuses and atrocities.
(Actually, sadly enough, if you said "socialism" or "communism" to far too many Americans, they'd think "Hitler." But that's another story.)
So that's the first part of the problem. The second part is that somehow (I can't say I understand exactly how), the far right wing in the US has, over the past 3-4 decades, managed to sell the idea that all wealth that people have they earned with the sweat of their brow, and that therefore, anyone who's poor (and thus would need the services that are, collectively, socialist) must simply not be working hard enough. Also, the only way to raise the money for those services is to steal it from the honest, hard-working Americans.
And yes, this glosses over the fact that the wealth in this country has become absurdly tilted toward the super-rich (vastly more so than in the Gilded Age of the late 19th century), and that at least a significant fraction of them, if not a clear majority (don't have numbers in front of me) obtained their money not by the sweat of their brow, but by inheriting it, getting lucrative jobs as high executives because of who they know and where they went to school, and, increasingly, exploiting various oddities in the financial system.
My best guess/understanding of how this manages to convince so many Americans to vote against what is demonstrably in their best financial interests is that there is a section of the population of America that wants things to be made very easy for the rich because they either honestly believe they will become rich someday, or just have some kind of vain, hopeless dream of it.
