I agree with all this. In all sorts of human conflicts, even if all the relevant questions of fact and logic have been addressed to the maximum extent achievable by rational inquiry, there is still the inevitable clash of power and interest, which can be resolved only by finding a modus vivendi, or with the victory of one side, which then gets to impose its will on the other.

Among the available tactics in various types of conflicts, it is ultimately a judgment of value and taste which ones you'll see as legitimate, and which ones depraved. This is especially true when it comes to propaganda aimed at securing the coherence of one's own side in a conflict, and swaying the neutrals (and potential converts from the enemy camp) in one's favor. It so happens that I have a particularly strong loathing for propaganda based on claims that one side's pretensions to power are somehow supported by "science." I see this as the most debased sort of ideological warfare, the propagandistic equivalent of a war crime, especially if the effort is successful in attracting people with official institutional scientific affiliations to actively join and drag their own "science" into it. (It is also my factual belief that this phenomenon tends to make ideological conflicts more intense, more destructive, and less likely to end in a tolerable compromise, but let's not get sidetracked there.)

Yet, while the intensity of my dislike is a matter of my own values and tastes, the question of whether such corruption of science has taken place in some particular instance is still an objective question of fact and logic, because it is a special (even if difficult) case of the objective question of discerning valid science from invalid. Therefore, people can be objectively and demonstrably wrong in seeing themselves on the side of science and truth against superstition and falsity, where they are in fact just engaged in a pure contest for power, whether in their own interest or as someone else's useful idiots.

Now that I've written all this, you might perhaps understand better my antipathy towards these "let science help us resolve moral questions!" proposals. People behind them, whether consciously or not, strive to recruit and debase science into a propaganda weapon in an ongoing struggle for power, not to resolve and end this struggle by reducing it to a rational argument. The latter is impossible even in principle, since the ultimate question is who gets to impose his values and preferences on others.