They probably weighed the odds that analog sticks would be too imprecise to handle the game without magnetism guiding some aspect of the gameplay, and that however imperfect the solution might be it tested better than just going no magnetism.Crazy that it's even on by default - I guarantee that most reviewers didn't notice.
As for reviews not noticing: that's hardly surprising as I highly doubt many if any reviewers at the big sites understand what bullet magnetism even is much less that a game might be better with it removed. Most of them grew up playing shooters on a pad and not a mouse so the whole idea of bullet magnetism guiding ballistics is so ingrained into their minds and playhabits that they likely would have thrashed the game just the same for feeling off had it been missing.