Furthermore, backing up Dan's point, commentarist is not in the OED.com. The closest thing that this guy could be looking for if he doesn't want to use commentator is commentariographer which is a centuries old word that is dated and rare.

commentariographer

Obs. rare.

A writer of commentaries.
1576 FLEMING Panoplie Ep. 220 C. J. Cæsar the comentariographer.
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"I always find it funny when chicks say that, because I hate sex but I still have it. Afterwards, I hate myself, I feel awful, dirty and sometimes cry. But it's worth it, if only to feel a little human every now and then."