Probably the fact that you will need to keep the old name alive to reference it in older litterature anyway. So old name will still be there forever and makes the name change a bit moot.
Maybe they are worried it adds cognitive complexity.
They may think it will be very difficult to enforce the usage worldwide. Some people won’t care and keep using the old name.
They could be afraid, it opens the field to constant renaming because the meaning and the disposition toward word changes all the time.
They might be worried they’ll have to waste time constantly arguing over name change and in fine decide who has the right to be offended by what. Maybe some of them would rather be doing their research instead.
Maybe they don’t give a fuck if it offends someone.