In order to make a statement that they are very susceptible, don't you think you could provide even a single example of it ever happening? No, you can't because there have been zero reports of this happening.
As a computer engineer, I can tell you that using a battery instead of gasoline has absolutely no bearing on whether a car can be remote controlled.
as a computer engineer, I will assure you an all electric vehicle will be susceptible to remote shutoff.
the fact that such a system would be physically hooked to a charger would also be far too tempting not to build in a back door. such a system would also have ‘call home’ capabilities to download various bits of data while being open to remote commands.
and there are examples of the electronic systems of cars being remotely accessed all over the net. do you need assistance with google?