That still doesn't answer the question of why, though. Saying that money shouldn't be the sole motivation for writing suggests that writing has to be more than a job for people. Why is that? If I work as an accountant because I need rent/grocery money, that's okay, right? Some people might do it because they love crunching numbers, and that's cool, too. It doesn't automatically make me worse at my job just because numbers aren't my passion.

Yet people still think writing is different somehow. There's this attitude that you CAN'T do it for money alone, or somehow it's BAD. People can't explain why it's bad, it just is. That's an emotional argument, not a logical one.