The main source of the Yasuke story was from Jesuit chronicles and Jesuits were known to make up a lot of crap.(it should be noted that Jesuits were famous for having jewish converts btw and they came from Spain and Protugal that were countries that made their jewish population convert. The current globohomo Pope is a Jesuit incidentally)
. Nobunaga never mentioned Yasuke in his own writings. Which given that Nobunaga would write poems about pretty much anything he laid eyes on, suggests that the two never met. The sole corroborating account stated that one of the jesuits had a black servant, and they presented him as a curiosity to Nobunaga's court, but there is evidence of nothing else.
And here's another strain on historical credulity. Supposedly Yasuke fought for Nobunaga as a samurai(Even at this , this is ridiculous because samurai were the nobility caste you had to be born in to a samurai family to be a samurai , you couldn't just "become one"). One of the claims is that he spoke fluent Japanese.
The time period between when they supposedly met and when Nobunaga was assassinated by Akechi Mitsuhide was... three months.
A black guy from what would now be Morocco, probably a slave to the Jesuits , and someone whose language skills would have included mostly broken Portuguese, supposedly learned one of the most difficult languages on earth in three months. For reference, Japanese has three formal alphabets.
There is nothing about the story that is historically credible. There is more evidence of Santa Claus than there is of Yasuke.
There's a reason why Medieval Japan aggressively expelled the Jesuits and called them spies that were looking to subvert and conquer Japan.
You have to wonder if the "Yasuke" myth started out as a joke or a way to insult the Japanese. A joke to undermine the Japanese by saying, "this country is so backwards that they made a nigger (or neger if Dutch, I guess) a warrior of nobility," or an insult by saying, "look at how undeveloped these Japanese are that they are fascinated by black skin!"
These days Yasuke is now just another tool to deconstruct Japanese history and destroy the cultural identity of Japan. It's a wedge to slowly split apart Japan by using that one black guy as a means to justify the worship of blacks and import street-shitters into the country.