BladePilot,
I think you'd have a point if:
(i) when they booked, the passengers couldn't find information about the maximum weight they were allowed; or
(ii) the passengers were told one thing at the point of booking and found at the airport that the actual allowance was less; or
(iii) other carriers' excess baggage charges are significantly lower than Ryanair's.
I have some sympathy for passengers in the situation, but not much.
What part of the "three bags, maximum 15kg, no pooling" regulation did they not understand? It's not rocket science.