Relative few? Anyone w a decent standard of living including 100% of people reading this are part of the problem.
And everyone not part of the problem wants to be (no one in a sustenance situation, except maybe some of the few tribal people on the planet, wants to stay there)
We are all the 1%, sure the .01% wastes vastly more than us but we can't pin it all on them. Our Amazon purchases, car driving, air travel, having our own apartments, etc are our responsibility.
What does that even mean? Who else is responsible for your lifestyle?
Thats true but everyone wants their kid to have more (use more, consume more, travel more, have access to more) than they did.
No one is saying poor people are the problem in overpopulation, the problem is the myth that we can all become rich whereas in reality the planet is unlikely to even be able to sustain the current level of decadence of humanity.
There may be some theoretical possibility of a utopian future w vertical farms and everyone lives within their means but capitalism has fed us our whole lives the importance of having more, being better than our fellows. To accept a reality where we can all coexist as equals is also theoretically possible but it would take a lot of inner world by the masses (and why would the elites every encourage such a mindstate?)
One of the ways to make clear how big our footprint is per individual of rich countries could be to calculate the max amount of people who could live sustainable on Earth with that rich country footprint we have now.
My first wild-ass guess would be between 0,5% and 5%.