That's a good point about renewable energy sources.
I'd still argue it's reasonable to assume that ML will consume more power as use-cases for it grow (i.e. more and more models are trained), and, therefore, I don't think it's unreasonable to consider the energy usage.
Honestly - I think what you may have heard is "ML is bad/evil." And yeah some folks probably feel/vibe that.
That's different from "Like any other technology the full context of ML deserves to be considered, and since it's so hyped by billion-dollar companies right now, maybe a bit of pushback on all the hype isn't a terrible idea."
And yeah we should definitely look at the airline industry; pretty sure Mother Jones does, and there's no reason we can't look at the energy impact of multiple industries.