ah, the fatally flawed Jedi philosophy.
"I will not use my powers for personal gain--" so you'll be a parasite on society, instead? Or eke out a living doing what you are only half-arsed at? It is not a sin or evil to get paid for what you are good at doing. In fact, morally coherent people recognize it as an imperative.
"I will not allow myself to feel fear or anger--" these are called psychopaths. No wonder every Sith for 10,000+ years came out of the ranks of the Jedi. Both the Jedi and the Sith have pathologically unhealthy views of human emotion, but the Sith at least do not deny or repress their emotions.
And yes, psychopaths. Consider the actions of the Jedi in the prequels.
Do good people steal away children from their mothers?
What kind of mentally healthy person tells you to shun form NO emotional bonds or connections with others? Does an emotionally healthy person look at a room full of child corpses and not have an emotional reaction, like Yoda did? Or encourages a man worried for his lover to REJOICE that she was going to die? Or use an army of CLONED SLAVES--- men who had their free will removed and their capacity for independent thought genetically removed--- as cannon fodder in a war? What kind of "order of the Light" discovers a planet ruled by crime lords and rife with slavery, and DOESN'T return with an army to purge it? Is it mentally normal for a boy to be rescued from slavery, and then NOT return to free his mother for over a decade... because his masters told him to purge all 'worldly connections?'
How can they revere a Force created by Life and Love and that binds together all living things-- and then steal their 'acolytes' from their families as mere infants and train them their entire lives to their emotions, abhor love, and sever all binding connections with others?
We lock people up in padded rooms with that kind of soulless lack of empathy.
The fundamental failure of the Jedi was assuming that because the Sith were bad, that THEY were the good guys.
It's far more likely that the Force was restoring balance not by ending the Sith but by purging the galaxy of the corrupt, emotionally stunted and sociopathic cult known as the Jedi Order like cutting out a cancerous tumor.
Of course, without fail will come the commenters whose counter argument is little more than "they don't really mean that." In spite of the Jedi Order BEHAVING precisely like that for the entire prequel. Even in the original trilogy Yoda and Obi-wan were no prizewinners. They dumped Luke on a desert slave planet and left him to live in hardscrabble poverty, lied to him, kept vital information from him, and ramrodded him through combat training in mere weeks (that strangely enough used to take Jedi padawans their entire childhood) all to use him as a weapon to kill the Emperor and Vader.... and then when he slipped the leash, immediately made plans to go try and use his sister, next. "Don't worry, there's another we can use--" conniving little bat-eared frog.