It is not a straw man. This is a common problem when discussing terms that are difficult to define when they are applied to actions that we simply cannot determine where the motives arise.

This is a quote from the book i am reading on a topic similar to this discussion about the concept of "Hedonism." Where hedonism attempts to explain that all human action is driven by what ever action will provide pleasure. He explains that not every human action, scientifically speaking, is about pleasure because some people just acquire money and don't spend it on things that bring pleasure. They just want to acquire money.

"They will claim that the miser actually gains pleasure by hoarding money. The miser is merely giving up the usual means for acquiring pleasure...but pleasure is still the end for which he/she strives. At this stage, the theory has been removed from the area where any scientific finding could possibly confirm or refute it. It has now become a philosophical rather than scientific problem, for no collection of facts can be gathered that would resolve the problem...[but] it can still be attacked on philosophical grounds. For when any theory cannot be refuted by the facts, then it loses its explanatory force. It becomes true by definition, but no longer refers to the world in the way in which genuine scientific theory does. "