Rspca and cat protections put down policys a disgrace

my mum's friend run's and elderly rescue, and yesterday recieved a call from a lady who was desprate for somewhere safe for her kittys to go.
She has tried both the RSPCA and Cat protection and been told by both that they were fall and the cats would have to be put to sleep.
There are 8 cats, two of which are only 8 months old, they are not unhealthy and have not done anything to warrant a death warrant so how can this be right.
Thankfully my aunty sammy, said she would take the cats and hold them for the lady till she found a new place having been evicted from her home. So these kittys will be saved, but how many other kittys and doggys die because of the RSPCA and Cats protection league unnessisaryily. My mummy will not support either charity in any context, and only supports kennels and cataries that have a no death policy, such as the dogs trust. giving your dog to the RSPCA could result in it being put to sleep so dont, go to the dogs trust or other kennels that refuse to put healthy dogs down, and save lives, instead of donating to the RSPCA and Cat protection league who willing destroy lives.
Us dogs didnt choose to be born people breeding us irrisponsibly and people not training and taking care of us properly resulted in us becoming the way we sometimes end up we need good people to help us become better pooches, not bad people who claime to be nice ending our lives just because of lack of space.