For example, the historian might be seen as a judge, offering an assessment of the rights or wrongs (according to his or her own viewpoint) of what happened in the past. One can certainly find historians who discuss the Reformation in this way, arguing for example that the Reformation was imposed from above, was not popular with most people at the time, and that it would have been better if it had not happened.
'... the historian might take the role of political campaigner ...'
It doesn't mean that this kind of historian is writing bad history, only that they have taken a particular line of argument. Equally, the historian might take the role of political campaigner. Another part of the impetus to looking at people like John Hogsflesh (rather than just studying Henry VIII) was the left-wing political commitments of various historians such as Edward Thompson and Christopher Hill in the second half of the 20th century.
They felt (and other historians still feel) that through showing the place of ordinary people in history, the historian could contribute to political discussion about the place of ordinary people today.
Yet again, the historian might take the role of philosopher, concentrating on the questions of knowledge and ideas that looking at history throws up. For example, the role of philosopher might prompt a historian to ask difficult questions about our 'knowledge' of John Hogsflesh, whether we can really know about what he said, did and felt, or only what the surviving records (created by powerful authorities) represented as his actions. (The gaps between what the sources tell us, and the past reality that is now lost, is another reason why various people have doubted that the historian can really be an objective, 'scientific' analyst).