You have to bear in mind that a lot of pirate gamers now were born well after the era of 56k/ISDN/ADSL and they didn't have to piece together games like the rest of us did. It's just a foreign concept to them that software can be split into parts.
I think it's more problematic that these parts are not done "like usual". I know I got pranked by it not once but twice.
For me, for at least 2 decades, it was always a one, continuous archive that is split into multiple files. You extract one, it will try to extract the rest. You mess up one, you won't be able to extract shit till you fix it.
I don't remember the last time (if ever) when someone did splitting OF ONE ENTITY (a game in this case) by literally making separate archives that don't "call" for one another and still calls it "parts". It makes sense for a tv series or some art collection but not here xD