I think it is mostly a reflection of Persson being reflective. "He" and "I" is straight from the story-line, while he uses "one" when he narrates the story-line to explain it for the journalist.

I think that is quite a common way to use "one", though it is uncommon to go back in forth between story and reflection, especially in politics. It might also be indicative of Perssons background. In some dialects one uses one quite a bit.

I had a swedish teacher who considered it sloppy to use one and tried to get us to stop using it. This would indicate that it is quite common, but not considered proper swedish, which could be why it is not normally frequent on television.

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