Comedy's Mother

There's an old medieval outline which some think is a summary of Aristotle's lost second book of his Poetics.

This is the second modern book I'm reading about this lost second book, but this time I am struck by an odd lack of symmetry in the outline itself. It states:

Tragedy... has pain as its mother.
...
Comedy... has laughter as its mother .

If you want to have laughter for the mother of comedy, mightn't you pick weeping for the mother of tragedy, especially if you're going for a theory of catharsis, since laughter and weeping are both shakers of your bodily self?

Although, it's true, for almost everyone, weeping is a less frequent experience than laughter. So maybe they are less parallel than I first thought.

Am I talking myself out of my critique?
Was my logic deplorably weak?