This-worldly pseudo-Christians cannot tolerate anything pessimistic, because that makes them feel despair

I have noticed that one of the barriers to (in the first place) valid Christian understanding, and (secondly) to a valid comprehension of how Very Bad things are in the world, now; is a mistakenly This-Worldly and Morality-Centred perspective. 

Furthermore, being this-worldly and morality-centred means that such Christians, almost-inevitably, are un-repentantly tainted by Residual Unresolved Leftism; since a TWMC perspective is also characteristics of the socio-political globalist totalitarian mainstream. 

Thus; this-worldly and morality-centred "Christians" gravitate towards a world view that could literally (non-pejoratively) be described as a type of Christianized fascism; since fascism was the early twentieth century's primarily-secular reaction against internationalist communism. 

Yet, of course, "fascism" is itself a species of Leftism - albeit a less complete and more-functional leftism than communism, socialism, or the current post-sixties "New Left"-ism.  

A Christianity that understands itself primarily in this-worldly and moral terms is catastrophically vulnerable to pessimism - where pessimism is understood as the belief that things in this world are already Very Bad Indeed, and most likely to continue getting worse. 

Anyone who is fundamentally this-worldly (whether self-identified as Christian, or not) will find it very difficult to avoid despair (which is, of course, a deadly sin) unless he is dogmatically and systematically optimistic; and this means that he cannot tolerate pessimism - no matter whether a pessimistic evaluation of this-world is valid or not. 

In other words, for the this-worldly "Christian" an optimistic understanding of this world is mandatory; and any pessimistic evaluation of current and future conditions is absolutely ruled-out, in-advance, by-assumption; otherwise the individual will be overwhelmed by despair.

This partly explains why so many Christians are so falsely optimistic about the condition of the world now, and its probably future; why they are so resistant to a realistic appraisal of this mortal life; and why they are so often drawn into advocating and supporting residually-Leftist and collectivist socio-political programs. 

Note: The answer to the impasse - which would enable Christians to be realistic about the nature and prospects of The World - would, of course, be to base one's Christianity primarily upon Jesus Christ's promise of  resurrected eternal life; as clearly set forth in the Fourth Gospel ("John").