Lucas doesn't really state that a person that gets upset and acts out of anger is evil. That is no where near the message Lucas sent, as some of his heros got angry and acted out of anger and never were portrayed as evil (best example is Luke). And to portray it a such undercuts Anakins fall, as Anakins issue wasn't that he got angry and acted, it was what he did when he acted out of anger.
While technically true, Yoda straight up says "once you start down the Dark Path, forever will it dominate your destiny." He also equates fear and anger to suffering and the dark side in his famous PT speech. It's a very easy logical conclusion to make that the Jedi of the PT are very narrow-minded and dogmatic when it comes to things. Obi-Wan's "Only a Sith deals in absolutes" line is a perfect encapsulation of how hypocrtical and blind the Jedi are to their own failings. Ulltimately, it was what destroyed them. Given how Mace treats him, its not surprising to think that Anakin would consider the Jedi Council distant, unapproachable, and judgmental. And let's face it,he did go to them. He went to Yoda with his prophetic dream and got handed a trite pop psychological book quote for "ancient Jedi Wisdom".
Qui-Gon was the only one who could have trained Anakin, because he saw outside the narrow confines of Jedi Dogma, and could have reached the boy, helped him understand things. Instead, he got accepted into an order who didn't want him, purely on a dying man's last wish, taught by a man who wasn't a terribly good teacher, and saddled with a prophecy everyone constantly brought up, but wouldn't explain to him. Finally, after seeing their complete stupidity in handling the "Ahsoka gets framed for murder" situation and their non-apology for hanging her out to dry, Anakin's sudden heel turn in Revenge of the Sith didn't seem so jarring anymore. I blurted out to all my friends in that scene, "God, no wonder he doesn't hesitate to kill you all."
Hyper-Emotional Young Man + Disapproving out-of-touch Elders + Warm, Open Manipulative Friend == "Are you actually SURPRISED he picked the kindly old man who always supported him over the riddle-spouting puppet and the condescending jackass who always looked at him like a mistake?"
Indeed.
Despite the melodramatic way in which the Jedi are "The Good Guys", they are in their own way as bad as the Sith when it comes to being dogmatic and blind to their own failings and imposing their unwavering vision of the universe on everyone they can.