'You are not entitled to your opinion. You are entitled to your informed opinion. No one is entitled to be ignorant.' --- Harlan Ellison
I would like to ask those who actively oppose the theory, have you actually read through the original reddit post or watched a video about it, or are you just opposed to it because you hate Jar Jar, the prequels, etc?
I have hated the Jar Jar character ever since I first saw The Phantom Menace, for the reasons most of you have provided. However, with the new light, that is the evidence this theory is based on, I respect the implementation of his character, and I am disappointed that Binks was never revealed as planned by Lucas himself.
The fact of the matter is, this theory isn't just "Jar Jar was pretending to be stupid to cover up being a Sith Lord," but is actually based on evidence both in the movies, and from direct quotes of the cast and crew from the movies, including George Lucas.
Honestly, I am appalled whenever someone rejects an idea or theory just because they don't like it, especially when they don't even take the time to understand all of the given points of an argument.
If after reviewing the material you still don't believe, fine, at least you now have an informed opinion. Here is a link to the original reddit post, and a video that presents the main and important points presented early in the posts history.