Water plumes or not, I suspect...
I suspect that suspicion is a code-word for ignorance.
Water is an incredibly weird substance. It's a near-universal solvent and has constituent molecules that are fantastically reactive. Both properties make it uniquely well-suited to supporting the chemistry that imperfectly-reproducing molecular machines depend on.
It's not too much to say that once you add water to the sorts of chemicals we know are relatively common throughout the universe, it's difficult not to get life, if you're willing to wait long enough.
As for energy: the last time I looked Ceres was not at absolute zero, nor was it chemically inert nor free from radioactivity. While it almost certainly doesn't have a molten core, if it has a composition similar to Earth's crust it's generating about a nano-joule per kilogram from radioactive decay (mostly 40K) which sounds small until you realize the total mass is almost 10^21 kg, so it's getting on for 10 TW in radioactive energy alone. It has a warm interior, with a thermal gradient near the surface that might well power molecular machines.
Also, Ceres orbits at just under 3 AU, so the solar flux on its surface is about 10% of what we get on Earth, which would make the integrated solar flux comparable to what is seen on Earth at about 55 degrees latitude in winter, well below the (ant)arctic circle. This region includes permafrost-free zones in Northern Canada.
Enough energy for life? Maybe, maybe not. But certainly a far stronger argument for the presence of life than anyone's "suspicions" against it, which only include information about the person in question and tell us exactly nothing about the world at large.
Posting "I suspect X (therefore, at least implicitly, you should believe X)" is exactly like saying, "I had toast for breakfast, therefore you should believe X". You have posted a fact about yourself (your suspicions, your feelings, what you had for breakfast) as if were in some way germane to a conclusion about a part of the world that is not you.