I've been percolating on this for a day or so now... because your responses on threads are generally abrasive, but i feel like most people actually feel this way and you just convey it abrasively. I think you should reframe anything from "wasting" to "learning from". You can have a lot to take away from even a bad situation, like:

a. Learning how to detect BS in interviews. Interviews are two-way streets.

b. Sit down and figure out what you really do want and how you ended up in this situation so it doesn't happen again.

c. 6 months over a career is nothing, and again, it wasn't wasted, its just the way you're looking at it.

d. Have you networked at all in these six months? If so, not wasted. If not, well that can only be on you not the company, right?

e. If you think non-profits are shitty, maybe a) they're not for you; b) you don't understand non-profits; and/or c) what were you doing there in the first place.

f. "screwing" a company is the same thing as looking out for your own needs (or in this case, the contractor's). There's good and bad contractors, of course.

Your observations may not necessarily be wrong, but to say it was a waste of time is short-sighted.

(edit: formatting)