Yes, did you vote in or fund politicians that were in favor of having intelligence services? If so, then you've voted for intelligence services given that will keep them going. If most of America did, then they likewise voted for intelligence services. I already know they did. :)

"I don't know anyone who agrees with the idea that spying for competitive reasons is okay. I'm sure there are plenty of people that do, but I don't think I've ever met someone who's stated as much."

Try this. Tell... "anyone" you know... to do a thought experiment. In this experiment, national schemes in economics and war have raged for thousands of years. Still happen. Many were prevented or reduced through information from intelligence services. Our competitive allies have them stealing our I.P., trying to win contracts, or trying to negotiate better positions in treaties. Our own spies have caught and reduced plenty of that. Our enemies have spies for similar and worse reasons up to and including killing a lot of us.

Now, with that backdrop, ask those people if they think we should have an intelligence service spying on those competitive "allies" and enemy nations. Mention that the alternative is to constantly be a victim of or behind those countries due to being in the dark with no spy agency. Which will they choose? I choose having a spy agency, using it for same purposes the rest do, and taking extra care to avoid it getting out of control or damaging.