It removes the conviction that one can espouse the rightness of absolute truth. Enter relativism and the end to unalienable rights. Witness Europe and the U.N.'s relativistic humanism. A plurality of people who have every conceivable justification to claim they know what is best, because evolution has been scientifically proven in their minds. Interpretation issues regarding the Holy Book's of the world, give open season to claiming no one can enforce their view of right and wrong in a sovereign way.
They believe the Judeo-Christian principles under girding American culture can be assailed on the point that science trumps the truth of our Bible. Determinism leads to stoic fatalism, removing the passion for truth and justice to prevail. Witness our Judicial System.
Eliminate our God of Judeo-Christian origins and immorality is rationalized on the basis of the IDOL called science. Science should be fun and helpful, but shouldn't politically be used to relativise the need for prayer in the lives of our children in the public square.
All things pivot on the justification Evolution theory places in the minds of it's adherents.
I disagree. But in a way, it really doesn't matter. The truth is not contingent on how we feel about it, and even if you're absolutely right - which you aren't ;) - the truth is also not contingent on the consequences. Essentially, the left will claim that scientific truth and the concept of universal moral precepts are incompatible and irreconcilable, and thus we must dispense with one or the other. You would seem to agree with them, although you would disagree about which one to toss out. But that's a losing proposition - for as much as we argue and debate and discuss evolution here on FR, the reality is, that debate is over, long over, in the scientific community, which is the only place that discussions of scientific truth really matter. The theory of evolution is a true and accurate, if not complete, explanation of the rise and diversity of life on earth. This is indisputably true. I realize you dispute it, but it really doesn't matter - in the forums where it does matter, the debate is over and the evolution-deniers have been shown to be wrong. And so you're forced into the untenable position of claiming that your belief in some abstract construct or another must trump verified scientific truth - you would force them to choose between morality and the truth, because they can't have both, according to you and the left. And I have a sneaky suspicion a great many of them will not embrace the falsehood of denying evolution as you wish them to.
But it's really a false dichotomy, in the end. There is no need to choose between the two, no matter how much the anti-authoritarian left wishes it to be so. Evolution and morality are entirely reconcilable, as witnessed by the vast number of people in this country, and on this forum, who believe that evolution can be a mechanism used by God in the process of His creation, and that accepting the truth of the theory of evolution does not mean that you must abandon all notions of morality. They understand that truth can always be reconciled with truth, and that denying one truth in the name of another serves no one but those who have something to gain by that denial. And they understand that people who have something to gain by denying the truth are people who are to be regarded with suspicion and distrust. Don't join those ranks in their minds, if you can help it, is my suggestion.