Based on this set of criteria, it is fairly clear that helper classes
fail to work well with two out of the five fundamental principles that we are
trying to achieve with Object Oriented Programming.
But are they evil? I was being intentionally inflammatory.
If you read this far, it worked. I don't believe that software practices
qualify in the moral sphere, so there is no such thing as evil code.
However, I would say that any developer who creates a helper class is causing
harm to the developers that follow.
And that is no help at all.