You’re severely misunderstanding. Objective means that something is absolute, independent of humanity, not without humanity.
A transcendent Being is necessary for a transcendent framework.
I agree with you, though the alternative is to believe in moral truths existing in the same way that mathematical truths exist. It would then be debatable whether such truths would require a creator God (just as it is a point of debate as to whether it take a creator God to have 1+1=2 or A=A).
But personally, I agree. This has nothing to do with whether or not God intervenes or answers prayers, so Deism is perfectly compatible with belief in an objective morality, as long as that objective morality would be discoverable through reason (and Catholics argue that it is, through natural law, thus would be granting that a Deist could discover that “murder is morally wrong” without the help of revelation).
It is also very important, I think, to point out that the existence of God and of an objective morality does not necessarily entail there is an afterlife. Likewise, to say that the prospect of no afterlife
must lead to a despairing worldview is assuming that a particular subjective or emotional reaction to the absence of an afterlife is the only “appropriate” way to feel (how does one prove what constitutes an “appropriate” emotional response or an inappropriate one?).
God could exist; meaning could exist; right and wrong could exist – yet there is no afterlife. Life would thus be
replete with meaning and significance, even though this life is the only one that God has seen fit to give us.
This a third way, conforming neither to the beliefs of traditional Christianity (God, objective morality, and afterlife) nor to nihilism (no God, no objective morality, no afterlife). It’s a third way because it says “God ; objective morality ; no afterlife.”
Simply believing in this would refute the notion that, if there is no afterlife, we must believe our lives have no meaning and no significance, and we ought to do nothing but despair. That’s a subjective response, and even traditional Christians would grant that the existence of God and of objective morality is sufficient reason to affirm that the universe is
not meaningless, independently of whether or not there is life after death. Frankly, however, even saying “no God, no objective morality, no afterlife” does not demonstrate that the only possible response – or the only response that “makes sense”-- is to despair. That itself would be a subjective viewpoint – one is making a leap between what one affirms to be case, and how one is “supposed to” feel about it. There may be no “how I’m supposed to feel about this” that is applicable. The statement “what’s the point of living” is a statement of opinion, as it is a subjective viewpoint as to what does or does not constitute sufficient motivation for “desiring” to live. Christians may only feel sufficiently motivated by an eternal reward, whereas one of a different constitution will feel sufficiently motivated by a temporal reward. Being “hard to please” – “I can’t be happy unless I live forever” — versus “easy to please” – “this is interesting; this is enjoyable; I’ll take it”–is a matter of temperament.