No, I didn't say people "mistake" materialism for physicalism, I said the way in which people use the word "materialism" is as a synonym for "physicalism" with respect to how it is defined in philosophical dialogues (and even in philosophical dialogues, physicalism and materialism are used interchangeably in this way). The colloquial meaning for materialism is the same as how physicalism/materialism is understood in philosophy: that nothing exists except matter, or that everything reduces to it. But it's worth noting that "materialism" is a term also used to describe people who are not philosophical materialists/physicalists, but people who value material possessions over other things or have a consumerist mindset. That clearly isn't what we are talking about here, though.