Why not? By your own admission, you are only working from personal experience, and anecdotal evidence is notoriously unreliable in drawing conclusions. Your statement that it is not disabling in any case, however, by saying that it is not a disability, does try to dictate how hard it is for anyone.
Being treatable does not make something less of a disability.
This is
generally regarded as being the requirement even after mitigating treatments and devices are considered, and many places require a duration of a year or more to consider it a permanent disability.
Limiting major life activities, rather than having better periods or even sometimes being controlled with drugs or therapy, is the definition of disability; neither you nor anybody else has the right to say that depression is categorically not a disability.