Dips are more pre-disposed to producing dysfunctional mechanics than most upper body exercises. When performed incorrectly, dips will wreak more havoc on the shoulders than just about any other movement.
However, when executed with perfect technique and appropriate body adjustments, they're actually therapeutic on the shoulders. It's important to master the correct form in order to reap the worthwhile benefits while avoiding the potential drawbacks.
It's very apparent to me that there are many coaches and fitness writers who don't understand the nervous system. I'm not the least bit surprised because your nervous system is arguably the most complex and ambiguous system in your body.