Yes, I apologize for being combative. I see your point now. I think I'm also wrong. I thought about my original response some more and this is a more coherent

Yes, I apologize for being combative. I see your point now. I think I'm also wrong. I thought about my original response some more and this is a more coherent version of what I was trying to say: A problem being in NP is sufficient but not necessary to reduce it to an NP-complete problem. But that's wrong. It's both sufficient and necessary to be in NP. It intuitively feels like you're tacking on more than you need to by introducing the "necessary" constraint, but it makes sense.