What you say is true but bitcoin is specifically designed to require massive amounts of computing power, which specifically equates to massive electric power consumption.
In other words its purposely designed to be excessively taxing on resources.
The other activities you mention have resource consumption as a side effect and not necessarily exhaustive.
A lot of electricity is used on other forms of security as well, such as SSL or password encryption. Although SSL uses up less resources, it is used by far more servers, which I suspect would exceed the amount of processing power of the Bitcoin network.
Individually SSL takes less CPU time, but in aggregate there is an awful lot of SSL traffic in comparison to Bitcoin. I suspect that overall the cumulative amount of CPU time spent on more conventional cryptographic security far exceeds the CPU time spent on Bitcoin's blockchain.
In other words its purposely designed to be excessively taxing on resources.
The other activities you mention have resource consumption as a side effect and not necessarily exhaustive.