Most people really don't know anything about encoding, so "few people" is probably inaccurate.

And I suspect that the distortions in the sound result from mass-encoding files from multiple CD drives simultaneously. About five years ago I had a (unsurprisingly old) computer that created the exact same noises when I played back CDs, which tells me that those sounds result from not having enough system resources to get the sound to run in a steady stream for long enough. It is likely that the people ripping the CDs are more concerned with quantity than quality. You've probably seen the computer towers that are a solid stack of CD drives; get the picture? I say that because physical music pirating in China (roughly 1/4 of all music media in East Asia is pirated) generates the same noise artifacts, and they most definitely are doing things the massive quick way.