Then there is no such thing as a moral philosophy. I've never met someone who derives their moral perspective entirely and only from a single source, within which they preference no particular element. There are no Christians, certainly, but also no utilitarians, no deontologists, no virtue ethicists, nor any other defined moral perspective. Anyone who quotes Mills is a liar, because they don't believe everything Mills did. Virtue ethicists are hypocrites who accept Aristotles' moral philosophy when it suits them but heinously reject geocentrism, which is also contained in his work.
Your black and white definition of what constitutes cherry picking may be emotionally satisfying, but it doesn't describe the real world very well, a world in which people are always negotiating a complex array of cultural and intellectual influences. Even if they come to prefer one school over another, that will never be absolute or all-encompassing, nor should we expect it to be. People are thinking organisms, not automatons. I note that your approach would lead to getting extremely sick if you actually picking cherries, and per your instructions insisting on eating exclusively cherries and every cherry, regardless of its degree of ripeness, health, moldiness, etc.
I'm not saying anything against being selective and "picking" your moral or cherries carefully. I am saying that if you are selectively picking from something, then you already have selection criteria / moral beliefs in place before you ever get to that "something". That logically means that "something" (i.e., The Bible and Jesus's words therein) cannot be the source of your morals, if you are using pre-existing morals to decide what to select from the Bible and Jesus' words. So, in the case of cherry picking Jesus' words, it means you are not picking your morals from Jesus or the Bible but rather you are just picking words use as a post-hoc rationalization for the morals you have already chosen.
If you go to a cherry tree and pick cherries. The tree and the cherries are not what determined which cherries you ate. You decided that based upon ideas you already had before you ever saw the tree.
Jesus himself used that same example. Picking fruit from a tree, I mean. Part of your discretion does, or should, include choosing the tree carefully. In the words of the teacher himself, "good trees bear good fruit." So the question isn't "why are you only picking ripe cherries", but rather "why are you picking cherries in the first place?". Your internal rule of
only picking ripe cherries is not your motivation for eating cherries, it's just a practical rule for not getting sick while you're at it.
If I find Mills'
On Liberty to be a useful moral guide, but also take into account the times in which it is written, that doesn't mean that I no longer consider it a guide to moral consideration at all, or that historical criticism is now the source of my morality (whatever that even means) simply because I am carefully considering which parts remain relevant and which have become obsolete, or meaningfully challenged by other writers, etc. I may well continue to find his basic principles useful, even though some of his specific examples no longer apply, or involved an assumption he didn't realize he was making. It can still be my favorite work on moral philosophy. I can still read it again and again, and call myself a moral utilitarian without any contradiction.
And since it is Mills, rather than YHWH, it would never occur to anyone to contest the label. The argument "you're being inconsistent because you claim to be Utilitarian but disagree with famous Utilitarian works on several issues" wouldn't make sense to anyone. Of course you do. You may
like Mills, but you
aren't Mills, and neither Mills nor Jesus would approve of someone reading their work uncritically, even a student of theirs. The way some people talk about interpreting Scripture bleeds of special pleading. Especially if the topic of discussion is philosophy and lived morality, why should preferring (but intelligently reading) the Bible be any different from reading any other favored prominent work on moral philosophy. Sure, some claim that God wrote every word of it, using his Cosmic Secretary to chunk out every line exactly as He intended it. For some reason, four Cosmic Secretaries, seemingly recounting slightly different versions of the same events from four perspectives as though in a deliberate attempt to confuse everyone. But if you
don't believe that, then not only is it okay to read the book more critically while still admiring it, I would say you have... well, a moral responsibility to do so. So the question is, do you believe the underlying claim? If not, there's no good reason to attempt, against all apparent reason, to defend it.
As to Jesus, if he wanted the so called New Testament to be written at all, let alone worshiped, he would have written it himself; the man was obviously literate, so why didn't he? And he wouldn't have taught almost exclusively in parables, a pedagogical form which absolutely requires critical thought, since most of them (and I would bet good money, originally all of them) contain no literal explanation of their inherently allegorical content. He was training up shepherds, not sheep, and he
said as much. You think it makes sense to read the bible like a moral instruction manual because you were taught to do so. Not because it makes much inherent sense to do so, and not because you have any convincing reason to think that Jesus would want you to.