Let me preface my comments by saying that I am no longer connected with the aviation industry. I now work in the petrochemical industry as a sort of glorified internal consultant to one of the big boys. Part of my job involves facilitating incident investigation.
Depending on the event I use a number of techniques: Why Tree, Tap Root et al.
Where you have a rash of 'small incidents' these need to be examined in detail to get at the root cause. Think 'Iceberg Effect'. You seem to be doing your bit but it is disappointing that management feels that giving bollickings is the answer. It rarely is.
From your post you indicate that these errors are 'human'. The good news is that humans make errors; recent studies indicate somethink like six per day. Good systems allow these errors to be trapped.
I would enjoy doing a Why Tree (essentially an extension of the 5 Whys) on some of your incidents. Attempt to get beyong the what, and the who (where your management seems to have paused) to find the systems level failure. Definition, the one thing that, if fixed, would have resulted in the event not occuring.
I am not sure if your management would buy into employing a professional to have a go at this or, if they did, whether they would be prepared to accept the results and recommendations.
Good luck.