The metaphor of language as music is fruitful.
When I used to perform music publicly, my teacher (Roger Jackson) gave me a bit of advice that I should follow more often. "If you make a mistake," he said, "make it proudly." His thinking was that more often than not, I knew more about that piece of music than anyone in the audience. He repeatedly assured me that the masses have no idea what note's coming next and they can't remember what note was just played. If you mess up a note (or seven) in Fernando Sor's Introduction and Variations on a Theme by Mozart from The Magic Flute, the only way the audience will know it, is if you grimace or react with shame.
My habit of wincing at a missed note had come almost certainly from an attempt to say to the audience I'm better than that mistake. If you caught that, please know that I did too. In other words: don't criticize me, because even if I didn't play it perfectly, I know this song as well as you do. Judge me not by what my fingers do. Listen not to which strings they pluck.
Makes no sense, does it.
I think of this every time I hear someone apologize for a word or a phrase they feel guilty using. But unlike a musician, who might slip from an accurate performance off a score, speakers who apologize, typically haven't missed or failed to meet anything other than an arbitrary and artificially enforced standard. I'm not speaking of errors such as spoonerisms or retrieval errors that are in fact mistakes of inaccuracy. I'm thinking of the false rules that English teachers have lobbied for and which many of the more assiduous students have accepted as proof of attention to detail. As proof of language skill. But which are little more than proof of a list memorized.
And the zeal to show that this list is mastered, can lead to this:
Maddow: …which the Democratic party inexplicably still allows him to keep. When he campaigns for Republican candidates, he is biting the hand that inexplicably feeds him. Pardon the split infinitive.
The only infinitive I can see in there is "to keep" and it's not split. What is Maddow apologizing for? Probably for the split relative pronoun/verb pair, "that feeds" interrupted by "inexplicably."
I don't have to spend much of this space shaking my head at how well-educated people know so little about the terminology of language and its structures. Labels are thrown around and terms are used without regard for their established use by people who study language for a living. Don't use the terminology of linguists just because linguists use it; use the terminology because linguists are among the only people who use it systematically.
Looking first at Maddow's confusion: a split infinitive typically refers to an adverb coming between infinitival to and a verb.
But here it looks like Maddow thinks a split infinitive is more generally an adverb jumping between a verb and another preceding word that feels like a unit with the verb. In this case, a relative pronoun, that, introducing the relative clause that … feeds him.
If the sentence was rewritten around the phrase the hand that continues to feed him, a split infinitive—to inexplicably feed—might be a less than optimal choice (if only because of ambiguity). However the ideal place would be pretty much in the same place as the sentence Maddow apologized for: between the relative pronoun and the verb
Any other placement of the adverb in Maddow's sentence would be either ungrammatical or awkward or misleading or at the very least, less clear.
This would mean either that he is biting in an inexplicable manner or that it is inexplicable that he is biting.
If this one is even grammatical it probably means that it is inexplicable that he is the one being fed. It could possibly mean what Maddow seems to be going for, that the fact that the hand is feeding him is inexplicable, (this is all so close to that old familiar complaint about sentential modifier hopefully). But that's a horribly awkward sentence.
This one is less awkward than the previous sentence but it remains ambiguous and, to my ear, leans towards the wrong meaning, sounding more like an adverb on the manner of feeding.
Altho Maddow's sentence is also ambiguous, the context is a big help in making the intention clear. It is pretty easily the best place for "inexplicably" as the sentence is constructed. And going with "inexplicably" is much better than trying to shoehorn a phrase like 'it is inexplicable that the hand feeds him.'
I assume Maddow is reading from her own script. So she has chosen, probably carefully, a structure that she feels she has to apologize for. It's likely that she chose the wording because she recognizes that it's a good way of saying what she's trying to say. In the metaphor of music, this is not a missed note. This is the chord just as she wanted. It came out just as she had hoped. So why the apology? Sometimes the self-reproach I mentioned earlier comes not because a flub, but because of an expected rebuke. In a sense, 'Leave me alone. I did that on purpose.' It's like performing your own composition and apologizing for a rasgueado because you know your audience would have preferred an arpeggio.
And my guess is that Doctor Maddow senses her fans are given to peevology. I have not enough evidence to make the same claim about Maddow's views on grammar.
Since this post has gone on long enough I'll stop before I turn to contributor Kent Jones, whose grammatical snobbery is thick and deserves a post of its own.