Yeah, you do make a good point about misattributing the system being incapable to their lack of research. But people don't like it when they are wrong/corrected most of the time. It also applies everywhere, computers just so happen to be the most prominent. The point is that people will complain about anything anywhere.

You bring up an example of installing Debian and needing non-free firmware for their wireless card. Take a step back and think how many people are even aware about the term non-free? It is quite a ubiquitous english word with different meanings in the open source community. People reading it will assume they know what it means.

The scenario when someone that is fed up with windows and decides to install debian will see the word "non-free" and attribute it to "you must pay" at glance. If the resource they used to install it mentions and clarify what non-free means, good. Otherwise, it can be a boogeyman for them and make them re-think their decision to switch.