Biggest problem here is that the BBC is the state broadcaster for the UK. They didn’t air anything except news on TV last night, BBC One & Two showed the same. Four was suspended.
They have a duty to announce the news in a respectful way, hence the simulcast. Maybe Radio 1 should’ve gone back to music earlier, but even if they did it would’ve only been instrumentals for longer.
This has nothing to do with R1 management and would’ve been decisions made by the highest & the Beeb. From what I’ve read elsewhere today, these are plans that are in place way ahead of time. Stuff isn’t decided last minute.
I get all the “should’ve done this to connect with the audience” stuff, but as state broadcaster the BBC has to be very careful. Commercial radio did offer an alternative yesterday, even sans adverts, so people had options.