You can only judge a person by their actions when they are adults. I doubt his mama and papa asked him if he wanted to go to Westminster; none of the people I know who went there were given a choice.
As an adult he was not concerned with 'cool' as it didn't really exist as a concept in those days.
As an adult he chose to renounce his title - something which was far more meaningful then than it is now.
He does have principles and he lives by them. He has always upset people because he does stick to principle, and is intelligent enough to recognise when an action which appears fairly harmless actually violates a principle, and he is intelligent enough to smash arguments which go against principle.
Therefore he is not popular with people who are a) not left wing enough, b) not intelligent enough to understand the importance and application of principle, and c) not principled enough.
These days, he gives some people the impression that he is bonkers, but he is speaking from a depth of understanding and a depth of experience which is quite foreign to a lot of people. My dh, for instance, thinks he's barmy.
The time was never right for him to become PM, but I wouldn't be surprised if he never really wanted the job anyway. I, for one, would have loved it if he had been PM.