There must be more to the story.
How long was the comm lost for? Seems like they were surprised. Refusing them to fly to final destination seems quite strange and an overeaction.
The North Sea has quite large sectors compared to flying through Maarstrict, so not anticipating a frequency change every 5-10 min could have made them too relaxed.
121.5 seems to have become flooded with unnecessary calls like ME carriers calling eachother, PAN PANs every where in the UK, when someone lost their orientation or practicing is as someone mentioned. (Get a flight info frequency for that) It often happens that you have to turn down the volume or you loose parts of a message due to unnecessary chatter.
I am not trying to make an excuse for the crew, as they should have been listening to 121.5, but there are many factors in this and maybe ATC forgot to hand them over. Has happend to me before, but 121.5 saved them from giving us an escort.
