> Don't you have blind peer review?
It's fundamentally impossible because when you publish the topics are going to be in a way or another niche enough that you know all of the people working on those topics and conferences make those circles even more public.
Say that you are studying e.g. "helical peptides", which is a vague and broad term on one side, on the other one, all the people that work on specific aspects of helical peptides (say, using them to bind surfaces that are very different in polarization, e.g. batteries) know each other and blind review would add nothing really. Even when it is blind you likely know who's reviewing it most of the time.
There are topics that are of course wider.
To make a comparison with programming: imagine you're involved in an open source community with a language that is niche enough that you know most of the people involved in it (it is common for many lisp dialects).
You can likely be given a program in that language and figure out likely who wrote it due to their interests, programming or api designing, or the use of static types, or some kind of linting that you know only a handful of people use, background, etc.
With the huge difference that in case of science the circles are much smaller because you know all your peers are in academia, who of them has specific instruments (not everyone has the same lab equipment), but who doesn't also have some others, you may know that some of your peers have their niche and "main branches" of research so you figure those things much easier. Also, in those circles you also know who is involved in your "code reviews" so if you know that A and B aren't reviewing it (you know they would've told you) it can only be C, D and E, but the feedback requesting this kind of experiment could only come from "C"...