The title sentence is one I hear from time to time, and seriously dislike it.
For one thing, it implies that it's impossible to love writing and still want to get paid for your work.
For the other, it often sounds as if those saying it see themselves as better than those who write for a living.
And frankly, to me it sounds like: "My writing is not good enough that anyone would want to pay me for it, so I'm going to put down those who manage to sell their work." Not to mention that I often hear it either from people who are financially supported by their parents (regardless of their age), or from those who do something else for a living, like to write, but for various reasons don't give their writing serious effort and don't dare to attempt to make it more than a hobby.
As for me, I love writing. I couldn't imagine my life without it. And the main reason I want to get paid for writing is so that I can write full-time, so that I don't have to do something else for a living and write only when time/energy/circumstances permit.
And besides, is there anything better than doing what you love most and being paid to do it?