Not defending banks at all, but they support much more transactions than Bitcoin or any other cryptocurrency. So if we compare the consumption of electricity by each, then we should remember the number of work done as well.
That's a good point.
Currently, the bitcoin network consumes more energy per transaction than banks.
But if you'd compare this all with the LN being used as proposed (assuming the development progresses as expected), i'd be sure that the bitcoin network would consume by far less energy for the same amount of transactions.
This of course does require the LN to work as expected and to actually be adopted. Whether this will really happen in the future is unknown. Only time will tell if its going to work as expected.
One thing is safe. If it is going to deilver what it promises.. scaling, fees and energy efficiency shouldn't be any reason for FUD anymore.
And banks will be way less efficient compared to the capability of the proposed network.