Do you really believe hundreds of millions of dollars a year was spent on electricity to keep mail servers running in the 80s or are you just trying to make the Bitcoin = early email argument in a really bad way?
Seriously, add up the billions upon billions we've spent as an industry (in terms of $/KwH delivered to all the datacenters across the world) over the past, say, twenty years, and bitcoin looks downright anemic in comparison. [1]
You might not like that people are choosing to spend money on electric for BTC, but if they weren't, I imagine that juice would just be spent on serving up pics of cute cats with a side of advertising and tracking. Be thankful we found something slightly smarter to do with it.
[1] http://www.nrdc.org/energy/data-center-efficiency-assessment... - 13 billion a year for power to U.S datacenters, according to the NRDC. Slap a moving average on that, account for non-US usage, and scale it back twenty years to the launch of Netscape Navigator and the subsequent rise of colocation, and we're talking more money spent on electricity for the Interweb than most nation states annual GDP.
Even a bubble sort will eventually get you a sorted list, but there's a reason we don't actually use it in practice.