[Pseudoscience-is-malarkey (OP)]

Why do some people prefer their coffee beans coarsely ground? It doesn't get absorbed into the coffee well.

[alancalverd]

Depends on your coffee-maker. You need a fairly coarse grind for a cafetiere, so you can filter out the bits with a coarse metal grid. Even coarser for a percolator, but paper filters have a short contact time and somewhat cooler water, so need (and can use) a finer grind to extract the same quantity of solutes.

Being very old school, I like percolated coffee - multiple cycles really squeeze the last milligram of caffeine into the cup!