This might be wrong, but I perceive the UK and France to both be the most "enlightened," or liberal, places in early nineteenth century Europe, whereas Russia and Austria would be the most "conservative." Why was the UK the most committed to Napoleon's defeat, when they had the most in common?
Maybe I am completely wrong on this, but when I think of the countries that had the most liberal thought, and the leaders of the Enlightenment, I think of the UK and France, and to a lesser extent the low countries. I tend to think the HRE, Austria, and "Germany" were very progressive on the science side of things, but still super conservative when it comes to politics.
I'm not saying I would expect the UK to embrace Napoleon, but I would think they would be the most likely to think he is someone they could work with, and reach and understanding with. Whereas I would think Austria and Russia would be completely dead set against him. But in reality it was the opposite, the UK always strongly opposed Napoleon, but Austria and Russia were sometimes his ally.
Now I guess the main thing is that Napoleon could get at everyone in continental Europe, but he was never going to rule the sea. But still, I would think at some point the UK would think "we don't like him but we can work with him."
So why was the UK so devoted to taking down Napoleon? Was it because of geopolitics and had nothing to do with ideology?