Is this 250-word sentence grammatically correct?

The single most important reason Miss Katherine Shallot was, at the incredibly unstable and defensless age of twenty-one, decidedly emotionally unavailable at all times to everyone she encountered and desired a relationship with, she realized, was not merely because she was desperately insecure and unsure of herself, her abilities, her looks, her smell, her voice, her walk, her poise, and her brains, but was also a combination of the many hurts and insensitivities that had been thrown at her by the various people that she had trusted throughout her life who, it stands to reason after the examination of all available and objective evidence, cared less about the permanent (or, in better terms, irrevocable and unforgivable) damages that they may have been doing to her psyche and to her soul, but more about the benefit that they would gain from treating her as—to be ever-so-sincerely cliché—a doormat or a rug or whatever you may like to call it; they treated her on most occasions as someone who is a mere rung on that ladder toward success (which anti-capitalists very much like to attack in their motivational speeches) in a world that not only promotes self-assurance and self-motivation, but also encourages the use of any available, vulnerable human being (quite resembling the work of a puppet master) to gain prominence and success in various abhorrent societal constructs including, but not limited to: careers, education, politics, and general relationships in which a person has in mind something material to gain.