The historian Rudolf Gneist pointed out that the Tory policy of “non-resistance” after the Restoration of Charles II was essentially the older Stuart policy of absolute power, but on the defensive. Your view of split infinitives is likewise. Adverb placement has always been fairly free, grammatically speaking, in English: adverbs may be moved around for semantic, pragmatic, and rhetorical effects.

Then someone decided to write down a rule that said “No adverbs between ‘to’ and a following verb in the plain form”, and so people were taught for many years, until they came to feel (not believe, but feel) that it was a rule not of grammar but of morality. When the absurdity and folly of this rule became evident, it was taken to the Banqueting House and beheaded, but people who had been brought up on the rule still twitched when they saw a “violation”.

To ease the resulting tic, they decided to say “Well of course we can split infinitives, but only for a *very good reason*.” But there is no reason why one should be required to give a *very good reason* for this particular freedom, any more than for any of the other freedoms that the grammar of English allows and has always allowed. It is not the case that there is only one right way to say something, though anyone reading a usage book could be excused if they came to believe that the author thought so.