A proper test of that claim would require a poll, but since most physicists are not signed up for cryonics, don't make public statements endorsing it, and when specifically interviewed about it say they don't believe cyronics works, it seems fair to infer that most physicists indeed don't believe cyronics works.
Yeah ... you're simply wrong here, Wedrifid.
physicists are usually atheists
Really? I thought they were merely disproportionately non-religious?
Except that cryonics is actually in their area of expertise. And in the area of expertise of cryobiologists (the people who cryopreserve tissues in a way that can be shown to actually work).
Is it? Techniques for minimising the damage might be within their purview, but the possibility of reconstruction in the future?
Actually, no, technically that would be a subset of their field. But that isn't the same as everyone in that field being an expert in it. Or even most of them.
Really? I thought they were merely disproportionately non-religious?
I was using atheist as a synonym of irreligious, which was an imprecision, but according to the references I can find, scientists are indeed mostly irreligious or atheists:
"Scientists and in particular eminent scientists are mostly atheists, perhaps the only demographic in the West in which this occurs." - Demographics of atheism
Techniques for minimising the damage might be within their purview, but the possibility of reconstruction in the future?
I suppose nobody is really...
In the past, the Cryonics Institute has had a policy that said that they would not accept anyone who is not a member. This has changed. The policy now is that someone who has full legal authority over your body can sign you up after you die. It costs $36,250 to be frozen if you are not signed up, which is more expensive. They also will not do anything until you have been on dry ice for 2 weeks after they have been contacted, so not being a member is more risky.
This is very important news for anyone who is currently cryocrastinating. It means that you can drastically increase your chances of survival without filling out any forms. All you have to do is tell a loved one you want to be frozen upon death, and that you would like them to take responsibility for making sure this happens. This takes literally 30 seconds. Do it now!
This news might also be a reason to not sign up right away, if you think something better (like radical life extension or uploading) will come along in your lifetime. We should discuss this in the comments.
Edit: The general consensus of this discussion is that this is a really bad reason not to sign up for cryonics.