The trouble with your premise is that it doesn't just apply to local people, it applies to people in general. Incompetence is all around us. Notice that everyone is a local in the place where they live.
But local people at least have the benefit of knowing their own situations, which puts them ahead of some other rando who doesn't even have that and presumes to know better.
And hence, AS I SAID, people should collaboratively work together. There's no presumption - despite you recognizing that incompetence is all around us, you'd be amazed at how many completely obvious things are not done, and other things done very poorly
Which is a misunderstanding of the premise that locals know best.
No one thinks that going to someone and offering them ideas is bad. The thing people actually object to is imperialism, and they object to it because it's common. All over the place you see not just governments making rules from an ivory tower, but even well-meaning non-profits providing grants or resources with the requirement that things be done in a particular way with no regard for local conditions.
If you're trying to help someone then you shouldn't need to coerce them. Nobody was ever objecting to the cases where you don't.
Actually, plenty of people - including the person I was replying to - explicitly argue that locals know best and you're being imperialist by even suggesting that outsiders might have anything useful to contribute other than money.
And, yes, you do need to "coerce"/convince/persuade/retrain people across many dimensions - people are generally extremely resistant to change, and instead stick with whatever theyre already doing. Not all interventions are just immediately self-evidently beneficial. Eg. "Hey stop destroying your topsoil by every means imaginable - removing and burning all waste from the harvest, not planting in contours to prevent erosion" and much much more. That takes time to prove out and even then requires a leap of faith.
I do strongly agree, though, that "well meaning" non-profits are quite often completely clueless and, arguably, destructive. Often through the very gifts they give, which often don't even work, or at least go counter towards the necessary goal of developing self-sufficiency.
