The allegation that cryonics is pseudoscience reminds me of the allegations that Singularitarianism/Transhumanism are "atheist religion", "the rapture for nerds", etc. That confusion, I think, comes when people see the questions we're investigating — "Could we live forever?", "Could we end suffering?", etc. — and assume that we're answering the questions in a way similar to how religion does... or they don't even think to remember why they believe religion is bad, and they assume that it's the questions rather than the answers. Obviously, the problem with religion isn't the questions it asks, nor their motives for asking those questions; the problem is the way religion acquires answers to those questions. The same applies to seeking eternal life. Eternal life as a goal isn't wishful thinking; it's wishful thinking when people mistakenly believe that the goal is easy or has already been reached ("you can live forever if you believe in Jesus", etc.). Yet it's not surprising that many perfectly intelligent people buy into these memes. They are used to hearing completely bullshit answers to these completely legitimate questions, so they get to the point where the questions themselves set off their bullshit alarms, even in the context of attempting to investigate them within a rigorous scientific/rational framework.

The "singularity == religion" and "cryonics == pseudoscience" memes are comparable to someone in the early 1960s comparing the Apollo program to the story of the Tower of Babel, and then dismissing the program on that basis as a technically infeasible religious fantasy.