Satoshi didn't think bitcoin mining would take up this much power. He probably expected it to be more of a home mining thing instead of being on an industrial level.
I suspect he did. He predicted industrial level operations handling the jobs nodes do which I presume by extension would extend to mining -
https://bitcointalk.org/index.php?topic=532.msg6306#msg6306But I doubt if him or anyone else could've predicted how rapidly mining would develop into the beast it has become.
The energy = security thing makes sense until you calculate how much energy one transaction consumes at which point it becomes gross however you want to frame it. Yup, banking probably uses more. It also serves tens or hundreds or thousands of times more people, businesses and transactions.
Once there's a ton of users that becomes increasingly moot but for now it's not a good look IMO.