The problem is not that the flight has been diverted or delayed or canceled.
It is understandable that there may be 1000 or more good reasons for a problem like that to happen; the real issue is the approach ("policy") that Ryan Air uses in this kind of situations: no communication to the customers, no basic care.
The article says that other flights were delayed or canceled, but the airlines provided accommodation to the passengers.
On the other hand Ryan Air has kept silence for more than 3 hours and did not care of finding an accommodation for their own passengers. McNamara has declared that they will reimburse the expenses of the passengers upon request.
The general feeling is that they are always trying to save any single dime, as usual, which may not be an issue if it was not made on the skin of passengers.