There is a sermon I love, that talks about dealing with ambiguity, and in it is defined 3 levels of dealing with ambiguity, the second mirrors the claims made in the article. I'm just going to leave a big quote because it explains it so well:
The English writer G. K. Chesterton once addressed questions similar to those I have raised today. He distinguished among “optimists,” “pessimists,” and “improvers,” as he called them, which roughly correspond to my three levels of dealing with ambiguity. He concluded that both the optimists and the pessimists looked too much at only one side of things, and observed that neither of them can be of much help in improving the human condition, because people cannot solve problems unless they are willing both to acknowledge that a problem exists and yet retain enough genuine loyalty to do something about it.
More specifically, Chesterton wrote that the evil of the excessive optimist (level one) is that he will:
"defend the indefensible. He is the jingo of the universe; he will say, “My cosmos, right or wrong.” He will be less inclined to the reform of things; more inclined to a sort of front-bench official answer to all attacks, soothing everyone with assurances. He will not wash the world, but whitewash the world."
On the other hand, the evil of the pessimist (level two), wrote Chesterton, is:
"not that he chastises gods and men, but that he does not love what he chastises ... [In being the so-called ‘candid friend,’ the pessimist is not really candid.] He is keeping something back—in his own gloomy pleasure in saying unpleasant things. He has a secret desire to hurt, not merely to help. . . . He is using the ugly knowledge which was allowed him [in order] to strengthen the army, to discourage people from joining it."
(The reference to the army, I think, is talking about "God's army" (informally, e.g. the "believers"), as this is in a religious context)