It does seem really difficult for people to realise that politicians only tend to reply to these things because someone asks them about it. And woe betide the politician who said "I'm not interested in that" - they'd be pilloried or painted as out of touch weirdos if they did.
Well up to a point. Brown boasting about how he'd phoned to check on Susan Boyle's health was just a self-serving publicity stunt that no one forced him into.