I'm in the same boat, actually...I ran a startup from 06-09 that was in the college/university admissions recruitment space. I competed with some really unsavory characters, and I refused to stoop to their level.
A lot of the practices were - and some still are - all legal. But sleazy as heck.
It sounds like you might actually live by one of my guiding principles: do that which allows you to sleep well at night.