The will be from ought be fallacy

From page 33 of Brian Magee's Confessions of a Philosopher: A Personal Journey Through Western Philosophy from Plato to Popper:

I came to realize, then that what matters above all else in politics is what happens, not what people say about it. And for the most part what happens is independent of my wishes. In politics especially, people tend to allow their wishes to influence their assessment of reality, and to mix up the two even at conscious levels of thinking. For instance, all my life I have bet on elections, and all my life I have found that many people assume that what I am betting on is what I wish to occur. If I say to a group of people, "I've just put some money on the Conservatives to win the election," I can count on at least one of them to say, "I didn't know you were a Conservative." Some people carry the mistake even further and assert that for someone who is not a Conservative to bet on a Conservative victory is wrong, in the sense of not morally right. Some even go so far as to assert that if you support a political party you ought to think that that party is going to win....

Since politics and policy are relevant to the everyday lives of billions these cognitive biases are highly destructive over the long run. Though Magee no doubt exaggerates and caricatures for dramatic narrative effect I think we know what he's talking about here, wishful thinking of some sort pervades much of human cognition, and it is difficult to ascertain where emotional sentiment ends and factual priors begin. The blurring of normative ideological frameworks and positivist models of reality is so entrenched that it is often a good assumption to make that people will conflate the two. For example, to those who are not well acquainted with me I think a post like the one below, The paucity of libertarianism, which suggests that libertarianism is the weakest political configuration on the American scene in terms of numbers, might be a strong signal to them that I am not a libertarian. Of course, most of you likely know that I am personally strongly inclined toward a moderate libertarian political program. But as a matter of fact I simply accept that libertarianism is not popular, my personal preferences are not fundamentally relevant. Though being human of course they come into play during my cognitive processes, I try to prune them as much as possible from my conscious operations and I often enact a meta-strategy of disconcerting contrarianism to keep myself "honest." In general it is best not to get too interested in data which confirms one's expectations as opposed to that which confounds, because it is often the latter which manifests the greatest return on curiosity.

These sorts of issues regularly crop when the spotlight is on controversial and emotional topics. When it comes to religion militant atheists and ardent religionists are often very vested in selection biasing data to buttress the case that their side is ascendant. Of course, if your goal is to construct a model of reality which exhibits enough fidelity to the world out there to be a framework around which one might generate plans for the future these sorts of games are totally counterproductive. On the other hand, perhaps at the end of the day reality as it is is less critical than reality as it is imagined. The life of Lysenko illustrates the various issues rather well, as proximate incentives were at sharp cross-purposes with stated ultimate goals.