"I hoped the article would explain also why the above happens" If I had to guess, I'd suspect that it's because there are a couple of ways to get it wrong when

"I hoped the article would explain also why the above happens" If I had to guess, I'd suspect that it's because there are a couple of ways to get it wrong when plugging in a USB drive or cable. You can get the orientation wrong but you can also accidentally put it in at a slight angle and have it catch. In the later case, just slightly adjusting your approach would get it in, but because you know that there is a chance of you having got the orientation wrong, you automatically assume that that was what happened and flip the orientation instead and end up flipping it back when you realize you were right the first time. I suspect that the reason we make that assumption, that we got the orientation wrong and not the angle, is that that's actually what happens the majority of the time when we fail to insert a USB connector. We discount the angle problem because it happens so infrequently, and when it does happen we just get the impression that we got the orientation wrong, twice, which is something that sticks with us. Hence, the sense that there is a paradox about the orientation of USB connectors.