That Anakin Skywalker falls to the Dark Side is not a particularly shocking revelation. The knowledge that Darth Vader is the father of Luke Skywalker is a spoiler so ubiquitous in society that even children know it before watching Star Wars. Anakin's descent to Darth Vader is largely attributed to his mere draw to the Dark Side, but a Reddit theory proposes his fall was due to his humanity.
Anakin's natural human desires combined the Light Side of the Force and the emotionless ways of the Jedi Order create an agonizing internal battle. Because Anakin was conceived by his mother, Shmi Skywalker, and the Force itself, he is immensely strong in the force, but his human side calls to him constantly. But his human side is what gets him in trouble, as the Jedi Order preaches that passion and feelings -- specifically, anger -- are the path to the Dark Side, when in reality, they are simply part of being human. When Anakin is presented with an outlet for his passions through an offer to turn to the Dark Side, it's no wonder that he jumps at the opportunity. His "selfish" desires push him away from the Light and turn The Chosen One into Darth Vader, a key instrument for the Sith.
To quote TheMediocreCritic directly, "Anakin Skywalker is created by the force and born of a human. The living force is built into his human DNA. The force in him strives for balance, but the humanity in him yearns for free will. This makes Anakin genetically and emotionally imbalanced. He is unstable throughout his life because of this imbalance. The force controls his humanity while his humanity struggles to retain individuality in the face of preordained destiny. Neither side of him able to achieve its goal."
The theory also argues that Anakin deviates from the Prophecy during The Clone Wars, even though we first see shades of his human desires in Attack of the Clones when he breaks and rejects the policies of the Jedi Order, defying their requests not to form romantic ties. The theory simply espouses that, by defying the Jedi Order, he also defies the the Force itself. The problem here is that this theory assumes what the Force wants is in line with what the Jedi want.
In addition to this, there are several other issues that conflict with the theory. One of the most significant counters is built upon the foundation that Anakin didn't fulfill the Prophecy because he fell to the Dark Side; however, in doing so, he did bring balance to the force by destroying both the Jedi Order and the Sith.
Anakin exists as a destroyer of those who believe they control and understand the Force. As Luke observes in The Last Jedi, the Jedi Order had embraced several toxic beliefs over the years. Their regime created an excess of the Light Side of the Force in the Galaxy, which Anakin countered by evening the odds, first by destroying the Jedi only to ultimately defeat Palpatine and end the Empire. He then set the stage for Palpatine's granddaughter Rey to ultimately establish a new order, one that was built from both the positive teachings of the Jedi and an understanding of darkness. Anakin's actions created a ripple effect which resulted in the Force becoming balanced.
On top of that, the theory creates a divide between living beings and the Force when in actuality none exists. As Obi-Wan states in A New Hope, the Force permeates throughout all living things. Luke in The Last Jedi exposes that the Force is a mysterious power of both Light and Dark that cannot be comprehended or understood by any human. The Force is nature, life and raw power, and it can enact its will by guiding all living beings.
Anakin's human side is not separate from the Force -- it is still a large part of the Force that runs through him. The problem with this theory is that it misconstrues, much like the Jedi Order in the prequel trilogy, the will and nature of the Force. However, the teaching of the Light Side by the emotionless Jedi Order separated a person's humanity from the Force. Because Anakin possessed such strong passions and natural human traits, it understandable that he turned to the Dark Side because the Jedi tried to divide his human side from the Force, thus making this theory very plausible.