It's also immoral to expose isolated populations to all manner of the modern world's vices, optimized to be maximally addictive and maximally extractive, for which they have zero defense or even knowledge of their dangers.
But they're not equipped to decide whether they want it or not. It's like offering drugs to children saying they can choose if they want it. Children simply aren't equipped to make that decision, neither are people in these populations. I don't think we should keep them isolated, but contact should be limited initially. The technology we introduce them should be limited, enough to increase their quality of life and eliminate disease and so on without being utterly disruptive. Over time more technology and information can be introduced.
No population should be kept living a life we would consider extreme poverty out of some noble ideal. But we also shouldn't completely disrupt their way of life out of a different noble ideal. Wealth as we understand it isn't the only thing of value. Human connection, meaning anchored in community and deep roots, a sense of belonging and so on, are what really matter. Introducing modernity to such populations will sweep all of that away in one motion. These people would be left adrift in an alien world devoid of personal meaning, their only solace whatever addiction appeals to them most.
