Might this not be a case of not what you say but how you say it?
Shouting on the radio "YES YOU DO!" when ATC is asking them if they need to deice and posting "Iberia Cowboys" flight so and so. Perhaps not the best way to put your point across.
How about:
"IBXXX from XXXX we are next to you on the ramp and for your information we can see large deposits of snow in your wing".
and
"Iberia deicing procedures?" the other day bla, bla bla (ie the actual flight de-identified)
For the avoidance of doubt I do agree they should be told and they are cowboys if they did take off with a contaminated wing. I do not defend the actions of the IB crew.