Some (almost all people in some way) people dream of a world (or "heaven" or "enlightenment" or a "purified society after the revolution comes" ... whatever) that is always good by our little human standards ... candy cane trees and ice cream mountains. At least, they dream of some state much better than the present state. In contrast, this world of ours is less than ideal. That is an "idealistic" view.
Some people think of the world as just blind processes, going no place in particular. (I really abbreviate the description ... but this is generally a materialistic view of the world). Although seemingly dispassionate and "coldly objective" about the world, this view will often cross the line into asserting that the world is "meaningless" or "pointless crap" or "survival-of-the-fittest cruel" or just "we are born, we work, we die" ... some such bleak thing.
Both those views tend to judge that there is something lacking in the present state.
However, Buddhism is an existentialist way of being in the world-just-as-it-is, meaning the world before we impose our judgments and dreams upon it. We neither judge the world lacking in comparison to another ideal world, nor do we judge it cold and pointless and hopeless. We just let the world be as it is, and we go with the flow ... to such a degree that we can no longer see perhaps the divisions between ourselves and the world in the flowing. In that way, as Nishijima describes it, it swallows whole both materialism and idealism by finding this world, just going where it goes, to be ideally just what it is. And that way of seeing beyond "beautiful" or "ugly", "peace" and "war" is .... pretty darn Beautiful and Peaceful!
And more than words describing this "realistic" perspective, we must actually taste it in the practice-experience of Zazen.
Something like that. My description is not very artful today.
By the way, accepting the world "just-as-it-is" does not mean we cannot also seek to improve things that need improving. Having "no judgments" and having "judgments" about making things better can be like two sides of a single coin. It is not an either/or proposition. I think.