(I originally left Ubuntu for Mint due to horror stories about Unity. To be honest, after using 16.04, I've now got used to it).
So you have NEVER EVER voted for the leader of the UK.
In theory correct, in practice that's not how it works. To give a current example, I probably won't be voting Labour at the next election, not because I don't want my local Labour MP re-elected (as actually I quite like her), but because I don't want Corbyn as PM.
So who the leader of a party is does affect how you vote in elections, even if you're not actually directly voting for that leader as PM.
"If there isn't a population problem, why is the government putting cancer in the cigarettes?" -- the elder Steptoe, c. 1970