I think what you have to understand is that monad is quite an abstract concept. It is possible to give a specific example of a monad, but from the specific example, you won't fully understand it.
Here's the first sentence in the documentation for Java's Comparable interface:
"This interface imposes a total ordering on the objects of each class that implements it."
This assumes people know what a total ordering is. Total ordering is an abstract mathematical concept, not really more or less abstract than a monad. Clearly then, people don't have problems grasping abstract concepts. They just learn the definition and possibly bunch of examples and they're done.
I think the real divide happens because people in programming praxis are simply skeptical to the claim that monads are a useful abstract concept to learn and use in programming. Many years ago, some of them probably thought they don't need to know what a total ordering is.
I don't think anything can be done with the skepticism other than either take the claim at a face value, and accept that monads are a useful concept, or verify that claim by learning Haskell for instance.