Underlying this seems to be the assumption that those pesky governments, pushed around by public opinion, will keep on blocking or delaying terrestrial data centres, but space-based ones will be fine.

The idea that launch rates could increase to the rates required to launch gigawatts of computing into space, without attracting a huge backlash, is fantasy. And such a backlash would be entirely justified - the only reason why the environmental effects of space launch aren't a focus of environmentalists is because there aren't many of them.