Do Ego Defense Mechanisms Exist?

Partly inspired by this thread, but it’s a question that’s been pestering me for a couple of years. From what I understand, Freudian psychoanalytic theory has essentially been completely discarded as being untestable or impossible to demonstrate (or just a load of horse shit, as most people seem to put it). Does this invalidate the entire concept of ego defense mechanisms? Wiki has a beautifully written summation of the subject, and treats it as a currently accepted model of human behavior. I realize that much of this model was developed long after Sigmund Freud’s death, and was derived from foundations he laid down through work done by Anna Freud and others, and that its development continued well into the late 1970’s. This quote appears at the very end of the wiki article:

The Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) published by the American Psychiatric Association (1994) includes a tentative diagnostic axis for defence (sic) mechanisms. This classification is largely based on Vaillant’s hierarchical view of defences (sic), but has some modifications. Examples include: denial, fantasy, rationalization, regression, isolation, projection, and displacement.

So is it only Freud’s (dad’s) theories concerning root causes of behavior that have been discarded, and not the entire body of his work?