> the pollution that individual datacentres emit

This is a reductive framing of the problem. The power grid fuel mix is what determines most of this. There are some cases of on-site generation (which is definitely not ideal), but this can also be addressed with a better grid.

You can argue that the data centers shouldn't be built until the grid can catch up, which I think is probably the most defensible argument a Luddite could offer right now. I'd get on board with that one if it was presented rationally. However, it does appear that the environmental arguments are merely a means to and end for some. Quotes like this make it hard to not see the underlying goals.