It isn't all that surprising to me either. But for different reasons. They have no idea what they are talking about.
Do we think they know our online banking software uses the same kind of encryption? Probably not. Andrew Marr not knowing this is annoying. But an entire government being ignorant of it is deeply worrying.
I think they don't know because I've never seen any of them describe encryption in a way that would suggest they know what they are talking about.
I don't doubt that someone in government knows. Probably an entry level staffer. But whenever technology comes up (such as blocking types of content from the internet) the policy is always utterly ham fisted.
I agree that the policies are always ham fisted, but I'm not sure how you could have a policy that achieves the goal of blocking specific "bad sites" without it being ham fisted.
How would you achieve the goal of coming up with a non-ham fisted technical solution to a ham fisted problem?