You're thinking of waste too narrowly. That power wasn't available for other things, so more had to be produced to cover Bitcoin and the other things, which meant more of all the negatives that come with energy production. Does Bitcoin provide something valuable enough to human civilization to account for that? Could that value have come from a more efficient source?

Failing to account for externalities is how we get rapid ecosystem destruction (before even bringing in climate change). Those Bitcoins aren't innocent little bits on drives. They have a cost to the planet they're produced on and the life that inhabits it.

"Wasting" energy is required to make PoW work, but if we could achieve the same with PoS (and that seems to be the case since ETH is switching too) then it would really be a waste.

If gold could be found without excessive energy use then it would be a waste to spend a lot of energy digging for it.

If there was a good low energy alternative to PoW then it's a waste of energy to use that method of validation.

Like incandescent bulbs are a wasteful way of making light when there are more efficient ways.