Not true in the Star Wars Universe. The Light Side of the Force is not weaker than the Dark Side. They are equally powerful, but they just come with disadvantages. Sith become very powerful very early on in their training with regards to combat. But at the cost of slowly destroying their bodies and their souls under the corrupting influences of The Dark Side. Like an addiction, the Sith starts out controlling the Darkness....but ends up either being destroyed by other Sith or becoming a slave to the Darkness itself. ("Is the Dark Side more powerful than the LIght?" "No. Quicker. Easier. More Seductive.") Its why Rey turns away from the Darkness in the Cave during The Last Jedi. She realizes it has nothing of enduring value to offer her. The Light offers more enduring and more versatile power. But the price you pay is that it takes more patience and committment to cultivate....AND YOU HAVE TO STAY CONCENTRATED AND CALM in order to maintain your connection with it, and draw power from it. The reason why Palpatine, Grievous, and Darth Vader were such effective Jedi Killers is because they understood and took advantage of this weakness of Jedi and Light Side users. Get inside of the HEAD of a Jedi. Either by distracting them... making them angry or afraid...and you disrupt their connection to the LIght and you severely weaken them. That is how Palpatine was able to take out so many jedi masters at one time in Revenge of the Sith. its why Order 66 was so effective in storming the Jedi temple and why so many Jedi died at Geonosis (overwhelm them with sheer numbers). ...and its why Obi-wan was able to defeat Greivous and Darth Vader where so many others had failed. Obi-wan was a master of the defensive lightsaber form 3 (Soresu)....and his termperment was such that he had mastered himself emotionally. Like Anakin he came to the order as an older child, and had a temper. So he had to learn to master his emotions to maintain his connection to the Light. Where others had not learned this. The Jedi who learned to combine Light with Dark was Mace Windu. His fighting style (Vapaad) made use of dark emotions and the Dark Side of the Force....but mixing it with the LIght and projeting it outward onto the opponent. So it created a feedback loop where the more a Sight drew upon the Dark Side and used it against him, the more powerful Windu became. But without the Darkness affecting him. This is why Mace was able to defeat Palpatine 1v1. But the problem is that Mace was the only Jedi to ever utilize this without ultimately falling to the Dark Side. ...and its why Windu never taught it to Anakin, despite his asking to learn. Windu knew that if he had, Anakin would have succumbed to the Darkness.

. . . Finally! I figured out why he had a purple lightsaber. It makes so much sense now. My thanks!

Ummmm….. In the pre-Disney canon, it was purple because he used a rare Kyber crystal in his light saber that could only be found in a difficult to reach location (forgot the name). I’m not sure how Disney has explained it, or if they even changed it like they did for Sith Kyber crystals (which I think you’re referring to).

Red + Blue = Purple. He used light and dark. Purple.

I figured that’s what you meant. But I’m not familiar enough with Disney cannon to know if that is the current explanation.

It probably is not.I only watched the prequels myself. I had just always wondered why they chose his lightsaber as purple. And now I have this weird contextual understanding as an answer that makes sense! To me. >_> <_<

Samuel L Jackson wanted one. They wrote it into Star Wars lore after the fact.