What the article seems to be arguing is that historians without such dishonest intentions are necessarily reinterpreting history in light of the modern era, and are likely including their own and societal biases in their narrative. and there is no real 'objective' history. Is this news? This is the sort of thing I learned in history class as a teenager (albeit in simplified form). Primary sources are valuable but should be put through the filter of partial knowledge of a situation and personal bias. Secondary sources should be looked at with knowledge of the times around them and the potential biases of the author.
It's the intent that's always defined "revisionist" history to me, and the willingness to include things which are not fact-based, or are counterfactual.