- Yoda considers Luke to be the last Jedi because he adheres strictly to the Jedi Code and does not accept unconventional training methods like those used by the "Bokken Jedi."
- Yoda believes that the "Bokken Jedi" have deviated from the path of the light and are heading closer to the dark side due to their aggression.
- Yoda does not know if the "Bokken Jedi" have faced their trials and become true Jedi Knights, so he cannot consider them to be full Jedi like Luke.
Master Yoda tells Luke Skywalker that he's the last Jedi, despite Order 66 survivors still lingering in the galaxy - and Star Wars has explained why that is. As one of the Jedi Order's oldest and wisest Jedi Masters, Yoda has come to understand the Jedi Code just as well as he understands himself. This has caused Yoda to set very high standards for all ranks of Jedi in a way that's managed to misguide him in the past, most notably during the Clone Wars. Nevertheless, he still serves as a proper and wise master for Luke to finish the training that Obi-Wan started, something that sees Yoda consider Luke to be the last remaining Jedi.
This statement has made viewers scratch their heads ever since Order 66 survivors such as Ahsoka Tano herself were revealed to still be living during that very same time period. While Yoda may have been in exile on Dagobah, he still would have been fully aware of the Order 66 survivors who continued to make their way through the galaxy, as well as the other Force-sensitive individuals who sought training from these survivors. The question of why Yoda would make such a claim about Luke with all these other Jedi still running around the galaxy has been raised for years, and now, Star Wars has explained why that is.
Baylan's "Bokken Jedi" Insult Fits With Yoda's Views
Baylan Skoll is the one who assigns Ezra Bridger the insult of "Bokken Jedi," named after the wooden sword with which the Jedi train. In associating the term with someone like Ezra, who was born after the Jedi Order fell and trained by Jedi Knight Kanan Jarrus, Baylan diminishes him to the most basic level of what a Jedi could be. Just as the bokken is a mock lightsaber, so is Ezra a mock Jedi, one who seemingly takes the title without actually having any of the same power or purpose.
This perspective actually fits with the same views Yoda holds, as he would have also adhered strictly to the Jedi Code in terms of who would be considered a true Jedi. Yoda would not have approved of the unconventional ways in which these "Bokken Jedi" have been trained, even if it's by those who experienced quite a good chunk of their life at the Jedi Temple. The Stupendous Wave explains this in more depth, focusing on why Yoda didn't consider Jedi like Ezra, Ahsoka, and Kanan to be "true" Jedi.
Yoda Feared A Generation Of Bokken Jedi Tainted By The Dark Side
Navigating the galaxy in the aftermath of Order 66 required many of these Jedi survivors to sacrifice the stricter rules of the Jedi Code in favor of surviving. This caused many of them to become more aggressive than the Jedi who came before them, and certainly more than any of them had ever been before the fall of the Jedi Order - even while they fought as generals during the Clone Wars. That aggression was passed down in training from these surviving Jedi to the "Bokken Jedi," as many of them feared that their Padawans would face the same fate many of their peers did during Order 66.
In the eyes of someone like Yoda, this was a path to the dark side, no matter how important it was to survival. Any Jedi who was willing to embrace such aggression could no longer be considered a Jedi; rather, they diverted from the path of the light, heading closer and closer to the dark side. Some of this danger is seen in Ezra's own journey, where part of Star Wars Rebels actually sees him opening a Sith holocron and learning from it, though he was able to come back to the light thanks to Kanan's help. Still, adapting the aggression that's so characteristic of the dark side would never earn approval from Yoda, and thus these survivors and the next generation could never be Jedi in his eyes.
Yoda Had No Way Of Knowing Whether These Bokken Jedi Passed Their Trials
Jedi can only become Knights when they face their trials, which is the path Yoda set Luke on by telling him to confront Darth Vader. Passing this test would complete the transformation into a Jedi Knight, and given the fact that Yoda appears to Luke after the Battle of Endor with a look of approval, it's safe to say that Luke passed his test. These trials were the only way of determining who would earn the chance to rise from a Padawan to a Knight, and without them, the Jedi Order would be unable to tell whether a Jedi was truly ready to earn such an important title or not.
Seeing as the training process for these "Bokken Jedi" was already untraditional in comparison to that of the Jedi Order, Yoda had no way of determining if they faced their trials before taking on the title of Jedi Knight. Without this confirmation, Yoda couldn't possibly consider them to be true Jedi Knights, especially as someone who so faithfully upholds the traditional Jedi Code. In his conversation with Luke, Yoda implies that one must become a Jedi Knight in order to be a full Jedi, and that's why he asserts that Luke is the only Jedi left by the time he becomes a Knight.
What Yoda doesn't know, and couldn't possibly have learned, is that many of these "Bokken Jedi" have already faced their own trials. Ezra confronted Grand Admiral Thrawn and resisted a temptation from Emperor Palpatine in the process, and even Ahsoka herself came face-to-face with Anakin Skywalker in the World Between Worlds to learn one last lesson from her former master. While the Star Wars audience knows this and can accept the fact that Luke isn't the only Jedi in the galaxy anymore, Yoda never had the chance to, and that's why he still believes Luke to be the last Jedi left when he faces his trial and becomes a Jedi Knight.