If regular customers know what the incident is they can make an educated guess as to how long the disruption is going to last and therefore what alternative arrangements to make, that's why most want to know has happened.
Line delay amounts and service specific delay amounts are already communicated to the public.
As incidents of the same nature can vary wildly with regards to normal resumption of service, how can a passenger make an educated guess when its difficult for the railways to make an accurate prediction?
If I'm at an airport and my plane has been delayed by 30 minutes I don't need to know the specific reason....it makes no difference to me. It doesn't get me on the plane any quicker and I don't get home any quicker. All I wan't to know is when the plane will be there, when I can board and what time I will be getting home.
If some of you people think its management trying to hide information from you might I suggest using stronger tin foil for that hat of yours.