Star Wars: Darth Vader Had a Good Reason Not To Wipe Out the Tusken Raiders
Anakin Skywalker notably hated sand and Sand People, but as Darth Vader, he never sought further revenge on the Tusken Raiders for his mother's death.
The most well-known villain in the Star Wars franchise is still Darth Vader, whose presence continues to be felt in several ways throughout the saga. Though he mainly showed up in the "Original Trilogy" movies, his origins were showcased in the prequel films. The second of these highlighted a seeming vendetta between him and an iconic alien species, though this oddly never went very far.
The young Anakin Skywalker slaughtered a tribe of Tusken Raiders who had captured and tortured his mother Shmi. His hatred of them was palpable, though he oddly never took this to the next logical extreme. As Darth Vader, he had more than enough power to finalize his revenge and wipe the species as a whole out. He never did this, of course, and the reason for his lack of doing so may come from the Obi-Wan Kenobi Disney+ series.
Why Darth Vader Hates Star Wars' Sand People
In Star Wars: Episode II - Attack of the Clones, Anakin Skywalker goes back to his home planet of Tatooine. There, he meets his mother's new husband and his stepbrother, Owen Lars. Unfortunately, the reunion with his mother that he had hoped for didn't go as planned, as his new family tells him that Shmi was captured by the brutal Tusken Raiders, aka the Sand People. When Anakin sneaks into their encampment to save her, he finds her enslaved once again. Tortured and mistreated, she dies in Anakin's arms, which only further fuels the emotional fire in his heart. Enraged to no end, he promptly slaughters the Tusken tribe. His massacre included not just the men, but the women and children, too.
Noting how much he hates the "animals," Anakin collapses into the arms of Padme Amidala. This moment was one that put the already imbalanced young Skywalker onto his path to the Dark Side. He would become obsessed with protecting those he loved and keeping them from dying. When he eventually became the Sith Lord Darth Vader, he had more power and influence than he ever wielded as a Jedi. Given how vengeful Anakin was, there was no reason for him to have not taken his hatred of the Tusken Raiders further. This never happened, however, as shown by the events of the original trilogy and what happened in between.
Palpatine Kept Darth Vader From Slaughtering the Tusken Raiders
Tusken Raiders are seen in Star Wars: Episode IV - A New Hope, ironically attacking Anakin's son Luke Skywalker. Given how ubiquitous they would still seem to be on the outskirts of Tatooine, it's clear that anyone on the level of Darth Vader never acted against them in any major way. Again, the former Anakin Skywalker could have easily achieved this feat if he wanted to with the backing of the Empire. On top of this, the Tusken Raiders were seen as basic and animalistic, and it's unlikely that anyone would have missed them. Thus, there's really no reason as to why Vader never tried to finalize his revenge for what they did to his mother.
One explanation is that Anakin only sought vengeance against the tribe directly involved with his mother's mistreatment and didn't blame the species as a whole for what happened. With said tribe already killed off, his vengeance was complete. Conversely, there's the possibility of Darth Vader wanting to separate himself from his past as Anakin Skywalker, and acting in vengeance on that level would impede this goal. This is essentially confirmed in the series Obi-Wan Kenobi, where Palpatine actually tells him to let go of his past when it comes to the titular Jedi Knight.
If having another encounter with his former master was too low of a priority, then such petty vengeance on a race of lowly nomads would be discouraged by the Emperor on an even greater level. With this guidance and other things on his mind, Vader simply let the Sand People be, having long since spilled the blood of those who forced him to bury his mother.
Star Wars: Episode II - Attack of the Clones and Obi-Wan can be streamed through Disney+.