I guess they did it since Denuvo is generally known to cause performance issues in games.
So, reviewers gave scores on the denuvo-less game, which would have better performance, thus better scores, then they patched denuvo into it, so that they will get their drm and any performance drops will not play a role in any low scores.
But I can’t understand why reviewers can’t update their review… maybe it’s expensive for major reviewers?