Ask HN: Charging for niche app a money grab?

I recently created a simple iPhone app that solves a small problem for a niche group of people of which I am a member. I posted on one of the community's main forums about this app (which I'm charging $0.99 for) and all I received were complaints of a money grab. It's not like this small niche of people would make me a millionaire from this one app.

How has it gotten to the point where you will be vilified for simply trying to get a small return on your work?

Within a small niche do you have to be a prominent leader to avoid this kind of animosity?