Bitcoin is not humanity using energy. It is humanity flushing energy down the drain.
"But look at the sun man! That's the real waste"
Are you high?
A more useful perspective is "humanity uses more and more energy for computation". The many devices which enable us to post these comments burn energy. The astronomically high video-traffic these days burns energy. Modelling early universe, protein folding, advanced chemistry... every damn thing we compute has the cost of burning energy.
As an aside, let's not forget how much electricity gets used simply for heating. There's no shortage already of "smart heaters" with a nice side effect of mining you some coins while they keep your house warm. Anything environmentally wrong with that?
See, it's not the endgoal of cryptocurrencies to burn energy; it's simply a cost. Now, thanks to bitcoin, we can have economies of scale drive optimization of that cost: improving the core compute-per-joule ratio of our technology. With all the collateral improvements across the globe with regards to environmental impact.
Could you say that porn distribution industry "kind of by design" lead to people watching more and more porn? Regardless of the answer, thanks to that we can have fast internets now. Similarly with bitcoin: thanks to it, we'll pack more & more bitflips into every joule, up to the thermodynamic limit.