I understand the reasoning of the UK government as follows:
It's important to preserve soul and essence of things. When you photograph someone, you take part of their soul; similarly, when you photograph an object, you take part of its essence. The modern technologies created lot of soul-less people and essence-less things; to restore the world to its former magical beauty, we need more protection against soul- and essence-taking.
Now, I am not an expert in psychology of governments, but the UK empire is actually quite old. We have to consider the possibility that it may be getting senile.
The UK is a leading member of the Church of Capitalism, so "soul" actually means "ability to profit from."
When you photograph a cultural object, profiting from it without the creator's permission is very, very sinful, and an outrageous attack on the concept of Eternal Profitability and Financial Immortality.
It's important to preserve soul and essence of things. When you photograph someone, you take part of their soul; similarly, when you photograph an object, you take part of its essence. The modern technologies created lot of soul-less people and essence-less things; to restore the world to its former magical beauty, we need more protection against soul- and essence-taking.
Now, I am not an expert in psychology of governments, but the UK empire is actually quite old. We have to consider the possibility that it may be getting senile.