Why do reviewers say ice makers are so loud?

Noise is the single most consistent complaint across r/Costco, r/Tiki and verified-purchase reviews. Multiple owners say the compressor and ice-drop cycle are loud enough that they keep the machine near a sink or even in the garage. Nugget machines that advertise 40dB 'quiet' modes draw better noise feedback, but no countertop model reviewers cited is silent.