I think that's just semantic misunderstanding. Some people name as "idea" the combination of concept + execution proposal. Other's name "idea" as the concept alone. I don't think there's a right or wrong here, people just have different opinions of how to call what.

Personally, for practical purposes and pushing myself forward, I prefer calling idea something that has a clear execution strategy. If you have a brilliant concept but not sure how to put it in practice. Then in my opinion you got half an idea, and should work on the other half.