Okay angry fan. You say that Anakin is loyal. That he’s teaching Luke about loyalty. So his definition of loyalty is to betray the mentor he had for over 20 years. And not only did he betray him, but he plotted to do it before he even knew he had a son. I don’t think someone who is loyal does that. His definition of loyalty is to turn his back on the Jedi order that raised him. They were the ones that taught him the skills that he possessed.
And here’s the thing. The Jedi order tried to tell him not to let his feelings rule him. That just because he has a dream or a vision doesn’t mean it is going to happen. But he can’t accept that, can he? No. He’s Anakin. He’s the most powerful ever and he’ll find a way to save Padme. Even if it means conspiring with someone who is looking to betray the very republic he claims to serve. Yes, Palpatine was elected to his position. But, as you and I both know, that position came with limits. He continued to take more and more power, and the Jedi were concerned that he would not give that power back. After finding out he was a power hungry Sith, they did what they felt necessary.
Face it. Anakin was ruined by his own ego. Were there mistakes made along the way by his mentors? Absolutely. No one is perfect. But his mistakes were all because he refused to control himself. He let himself be ruled by fear and hatred, and that was the cause of his downfall. He wanted power, plain and simple. His ego was why he lost his family. His ego was why he lost to Obi Wan. And his ego is why he will never be as good of a Jedi as Luke.
As far as Luke learning nothing goes, what a load of crap. After finding out Vader was his father, he learned to process those feelings and find a solution. Vader turned back to the light side because Luke was the catalyst for it. Because Luke was good and Vader saw that. Vader has Luke, Obi Wan, and Yoda to thank for his redemption. Face it angry fan, Vader is to blame for what happened to him.