Tl; dr:
1. Distinguishes 60% reduction in living animals from 60% average reduction per-species. Then cherry-picks a hypothetical where the latter is less severe than the former (though it could be greater too).
2. Accepts that humanity has caused a huge loss in life, but mildly distracts by looking at "since prehistory" rather than the much more severe changes since 1970.
3. Concedes the distinction in point 1 is nitpicking, seemingly negating the point of the article.
4. Justifies itself with the explanation that without technical accuracy such claims are easy to mistakenly lump in with conspiracy-theories and ignored.