The BA crew were right to question the IB crew if they were concerned and follow it up with ATC. It is good airmanship so to do. I also hope they filed an MOR so that the incident can be properly investigated by the relevant authorities empowered so to do. If they did not file an MOR and then came onto this forum to publicise a specific event such that the crew can be identified then that is very wrong.
IF the IB did not de-ice when they should have done then that needs to be investigated by their airline and appropriate action taken. In extremous that may mean dismissal or demotion, it may not, depends on circumstances and none of us here has the complete picture.
This weeks flight has a very interesting article about the blame game.
We do not want to get into Kangeroo courts on Pprune.