Like, hypothetically, you have to get a car - it's not a choice - you only get to choose what kind and you can't wait for things to change or improve?

And, to be clear, if you want to 'reduce emissions' that is going to be something separate from 'rare earth mining and slave labor' - so it will be hard to compare directly.

But you could apply a heuristic that considers the long term consequences of one versus the other. The gas powered vehicle relies on gas industry infrastructure after all, and so buying a gas powered car reinvests in that infrastructure. And EVs, in contrast, do not - the purchase of an EV invests in the development of a non-carbon based energy system. So both have long term consequences, it's kind of a wash.

But ultimately how do you know if reduced emissions would offset the impact of rare earth mining? It's terribly difficult to see how that could even be measured, let alone evaluated. And because of the absence of any obvious choice it would probably just come down to making a personal, subjective, choice.

Like this "logic" is just trying to reason with limited information - and sometimes, as individuals, we must make choices before we have all the information we would like. Like we should definitely do more research, get more information, get better batteries, organize labor, de-colonize the countries being exploited by extraction industries - but those are long term projects that, if you have to buy a car to get to work tomorrow, aren't really going to help.