I don't think the suggestion is that developing countries should get to pollute their way into modernity the way the West did. As you point out, the planet won't care whether the extra pollution comes from a place of historical "fairness". But acknowledgement of the fairness element here does imply a straightforward (though far from simple) solution: massive transfers from those who've already dumped their pollutants into the atmosphere to those who are still in the development phase where they need to. Ignoring geopolitical realities and playing the global benevolent optimizer for a minute, this is a pretty clear-cut way to make sure that the externalities and benefits of pollution-driven development are borne evenly, while not ignoring the realities of the planet's response to pollution.

I'm not necessarily endorsing this policy. Just pointing out that the dichotomy you're setting up is a false one.