A friend of mine recently had an MOR "filed against him" by an ATCO and tried to discuss the circumstances with the controller and all he got was invective.
Looking at the circumstances I considered the controller to be "in the wrong".
The pilot could, in my opinion, have also have filed an MOR allocating blame to the ATCO.
In fairness when investigating an incident it is often the case that "blame" is often spread throughout the reporter and reportee.
I had an aircraft taxi through a lit red stop bar and I was also cited for a lapse in phraseology. Perfectly acceptable. The occurrence merited an MOR .The investigators looked at the circumstances and decided what happened.Lessons learned all round (me raising my game)and the MOR system doing what it was designed to do. As for discussing it the ATCO should not be drawn into discussing anything. Leave it to the Watch Manager(or equivalent) and then let the investigation take its course.