I think the BBC has handled this clumsily - not for the first time.
They are entitled not to renew a contract for an eomployee if they wish, and this is what they have elected to do - as they do with may employees.
If they had said something along the lines of - "We are refreshing the line-up ..." then no-one would have said anything at all.
They have kicked the hornet's nest by bringing in the 'D' word with all its contexts and provocation.
I am a regular listener to The Now Show and a fan of Mr Holmes, but everyone in entertainment has a shelf-life and a rolling contract is no guarantee of consistent employment.
The fault is with the BBC and their trendy language, instead of simply saying they are looking for new talent, and then quietly going about finding and introducing new people, they have now put instant pressure on whomever comes in to replace Mr Holmes, through no fault of theirs.
The BBC mess up again - no change there.