I mean, it's safe to assume that most of the "Bitcoin is a waste of energy" people probably didn't even spend enough time thinking to grasp the concept of "store of energy". That, along with the dozens and dozens of nonsense criticisms against Bitcoin.
As far as I know though, the argument against Bitcoin's energy usage is mostly in the environmental perspective. That Bitcoin is unnecessary hence is causing unnecessary damage to the environment. Funnily enough, people criticize Bitcoin's energy usage with them turning a blind eye on other "unnecessary"(not necessarily bad, but not necessarily needed for humanity to survive) energy hogs such as Christmas lights and gaming consoles.
The hypocrisy behind the opinions of those people is very obvious to anyone that takes the time to actually think about it, they say that bitcoin is wasting energy as it is unnecessary, however it is fair to wonder if civilization can exist without a sound form of money and there is not any form of money that is better than bitcoin, while a great deal of the energy that we use could in fact be said to be using completely unnecessary stuff, after all entertainment can be gotten without the use of electronic devices.