Why do so many Final Fantasy VIII fans and players like myself believe the R=U Theory is Credible?

An Elaboration on why people like myself still believe R=U is a credible fan theory.

Why I found the Rinoa = Ultimecia Theory so Convincing after I had beat Final Fantasy 8 on my backwards compatible 60 GB PS3

Why I believed that Ultimecia was an amnesiac Rinoa and how Adel was the key. Obvious spoilers for Final Fantasy 8.

Triangle (2009) was fairly good (Amazon Prime)

Note: This will contain Major Spoilers.