I cant say I really understand as I dont have the relevant experience.
But taken from the DPAC article:
In simple terms, campaigners say the ruling means the law will now class fewer people as being deprived of their liberty and if fewer people fall into that category, fewer people will automatically get the legal checks and protections that used to follow.
That could ease pressure on an overstretched Deprivation of Liberty Safeguards (DoLS) system, but campaigners say it does so by narrowing who gets protected in the first place.
They warn that disabled people in locked or highly restrictive care settings may now find it harder to get independent oversight or challenge what is happening to them.
So the previous ruling (Cheshire West) included a larger number of people with disabilities as being "deprived of their liberty" and as such they were supposed to get more oversight from professionals to ensure their rights were not being abused / overlooked.
But by getting rid of this ruling fewer people who may in fact need support re decision making etc., will now have the automatic safeguard of a professional assessing decisions.
I am sure it is not as simple as that, but as the article implies that part of the reason for doing this was to cut costs by having fewer people needed to oversee the rights of disabled people I thought it concerning.
There are such a range of contributors to FWR I sort of felt someone with experience or knowledge might be able to say if it really is a threat or just a "common sense" adjustment.