With so many plates spinning at the same time, I think it was something overlooked, though I'd love to think Negan's got an angle here.

Awesome question, by the way. I never connected those dots at all.

 

I think that's a pretty good observation. I had forgotten Negan saw the heliocopter. Might be what he meant when he said to Rick "When it falls apart, and it will, come back and tell me about it."

Knowing there is another organized group out there Negan might think there is a conflict to come.