Cassette players and chunky buttons are historically linked though. That there's no intrinsic fundamental technological connection and counter-examples exist doesn't change the fact that most people with memories of cassette players will have memories of chunky buttons connected to that. You're hung up on technicalities when the discussion is actually about nostalgia.

In an case, the author specifically cites the example of Ion Fury, a game which ships with a hardware renderer enabled by default but also uses nearest neighbor interpolation, so the premise that the author isn't aware that the aesthetic isn't possible with hardware rendering is mistaken. He knows. He's calling it software rendering because that's what the aesthetic is historically connected to.