Because physicists make a living from solving problems, so they have an incentive to create problems where there aren’t any. For anti-matter this works as follows. You can calculate that to correctly obtain the amount of radiation and matter we see today, the early universe must have contained just a tiny little bit more matter than anti-matter. A tiny little bit means a ratio of about 1.0000000001.
If it had been exactly one, there’d be only radiation left. But it wasn’t exactly one, so today there’s us.
Particle physicists now claim that the ratio should have been 1 exactly. That’s because for some reason they believe that this number is somehow better than the number which actually describes our observations. Why? I don’t know. Remember that none of our theories can actually predict this number one way or another. But once you insist that the ratio was actually one, you have to come up with a mechanism for how it ended up not being one. And then you can publish papers with all kinds of complicated solutions to the problem which you just created.Sabine Hossenfelder, “Where is the anti-matter?” at BackRe(Action) (December 4, 2021)
Isn’t she overlooking something? Why shouldn’t it have been one exactly? Are we trying to avoid something here? Why do so many asymmetries lead to our existence?