Those are not the only two options. Maladaptive traits decrease the frequency of the carrying allele over time (as they hurt chances of survival+procreation), a

Those are not the only two options. Maladaptive traits decrease the frequency of the carrying allele over time (as they hurt chances of survival+procreation), and even assuming that we're not catching a maladaptive trait in the process of being weeded out, its mere existence does not mean it's actually adpative, i.e., helping survival and procreation rates and increasing in frequency. Even assuming that the trait is mostly genetic, it can be neutral, it can be a common maladaptive mutation, and it can be a "net-positive" maladaptive side effect of an adaptive trait -- this is especially likely in a complex organ as the brain, which we know very little about. Assuming that a particular high-function brain behavior is adaptive just because it's there is therefore a stretch, even if it's reasonable to assume it's not severely maladaptive.