Expressflight,
Perhaps they needed to get the aircraft back to IOM to protect the rest of the day services, i.e. cancel one flight in favour of protecting the rest of the day!
The joy of scheduled services ... "Cancel, rebook first available flight"
Somewhere, someplace, there will be guys in a back room with all the information to hand and in the best place to decide which pax to upset and which pax to protect and often such is not obvious to airports and/or airport handling agents.