In high school I was prodded to get a job, so I looked in the paper, applied for a bunch of things, and eventually got one. It was a company that did telephone fundraising for charities, which at 17 seemed ok by me.
Very gradually I learned that it was run by scoundrels, and that only about 15% of the money raised actually made it to the charity in question. The work was awful, but I stuck with it because that's what you do with jobs. It was the realization that I was basically helping scam artists take money from big-hearted, too-trusting people that got me to quit.
Conscience isn't some fixed thing; it's a skill you learn, a habit of ongoing evaluation. If I can wake just one of these people up so that they, like me, go and get a job that isn't net harmful to society, I'll consider my time well spent.