It's interesting, because I don't feel negatively about cryonics (and back when I did I don't think it had to do with coldness), but when you suggested the normal-temperature equivalent I got a very different mental image.

That person, the one at room temperature who can be brought back later, is sleeping.

Meanwhile, cryo-related mental images are all science-fictiony. I'm thinking of Fry from Futurama and the Ancient lady in Stargate SG-1 and so on. I have examples of those readily available to my pattern-matching software (I imagine most people in the general population aren't as familiar with this sort of media) and I can think of the previously frozen persons walking around lucid and alive.

But they weren't sleeping. And sleep is so harmless, so inviting.

Edit: "Room temperature" should really have been "body temperature". But the distinction seems relatively small in my mind. I think the key is that you can touch somebody who's body temperature or room temperature, if you want. You can go pat them on the head or hold their hand. You can't do that with someone frozen.