Tim sets out six factors that can help us to understand the relevance of a politicians' private life to his actions.
To my mind the crucial thing to remember is that we are in a representative democracy. We can't judge politicians entirely on their policies because we are not just electing a manifesto but a set of oligarchs to rule for four to five years. Politicians can ignore what they have promised in their manifesto. Beyond that, they may be faced with conditions that policy could not be formed for before hand. Trusting someone with that kind of power is a big deal, advocates of mixing in some purer democracy might argue it is too much, and it is quite understandable that people should want to know the character of the person they are giving so much authority.
I think that actually presents something of an argument for ideology in politics. While ideology might be seen to corrupt people's decision making by introducing concerns other than a simple balancing of evidence and expectations it does at least make politicians predictable. Even if you don't completely embrace a politicians ideology if they take it seriously you do at least know where you stand.
Finally, I have to quickly respond to Tim's particular dislike of indifference (he laments that people are less infuriated by that than by hypocrisy). I actually think he is wrong on this. It would be a real shame if the Right were to replicate the Left's weakness for unserious 'caring'. The idea that, for example, even if someone's prescriptions for responding to climate change are lunatic it is, at least, good that they care cannot be something the Right accepts.