I'm pretty sure your terminology is causing a lot of needless confusion here. I think people are reading "cryonics doesn't prevent dying" as "cryonics does not prevent death", which is the usual way of speaking. If someone says, "Sam's dying; do something!" they don't so much want you to stop Sam from feeling like he's dying, but rather they want you to make it so that Sam does not die.

However, you seem to be talking about death in the following, and people's replies might be better directed towards this:

Well here it is: I can die. I can't be dead - because at that point there is no I. So while right now I can fear the void, it won't be a problem once I am dead. Note that insertion of cryonics does not change any of these facts. I'll still be afraid of dying, I'll still die, I will no longer exist. Whether I'm in a frozen can or my ashes are scattered in the ocean there will be an identical amount of neural computation. So I won't exist and I won't have any problems, either way.