The short version is even the seemingly well-meaning ones are making or alluding to promises they just can't keep.
The key problem with cryonics is that water expands into ice crystals when frozen, and the human body is 70% water. Tissues, including critical brain tissue, are destroyed. Dessication before freezing would also cause damage. Some firms say they have the secret sauce or are close to it, but nobody has answered this question AFAIK.
And then there's the longevity. These facilities claim to be able to run decades or even centuries, without failure, but that is an extremely high bar regardless of how much money you throw at it. Power fluctuations and equipment failure take their toll. There are already stories of cadavers turning into soup in their care.
It doesn't need to be absolute in success, it just needs to be applied arbitrarily to further abuse out-groups.