Sure, they may have gone with Yasuke because they follow the whole more minorities (especially black people) in media. Or maybe because they wanted their game to stand out? Or maybe both.
No, it isn't. This game was made by Ubisoft Montreal where African-American (or black people) violence on Asians isn't especially prevalent. The world doesn't revolve around the United States, nor does this game for that matter. It's a Montreal-based studio owned by a French corporation making a game featuring an African samurai in Japan, yet here you are linking it to US politics, and a very specific issue at that. Furthermore, African-Americans and Africans in the United States are two very distinct groups that don't even always get along (I would daresay, they don't get along at all). You're the one who made a connection to modern American politics by seriously reaching.
We can speak on societal issues if they have anything to do with the game, but what you're talking about has absolutely nothing to do with it, come on. You were seriously arguing that this game normalizes violence against Asians.
The portrayal of Asian men in western media as weak and effeminate is a discussion that can be had, but this isn't even the case in this game. Yasuke serves a Japanese man. Japan in this game even with the historical inaccuracies is presented in a very positive light. If you're going to fight over the negative depiction of Asian men in western media, this ain't the hill to die on. We're far from The Hungover that made a joke of Asian men with Leslie Chow and his tiny penis.
Now, if your problem is about the erasure of Asian men in western media and the fact that this was a golden opportunity to have an Asian man star in a video game, sure. Then again, Sony already beat them to the punch with Ghost of Tsushima, so I'm unsure how much positive Asian male portrayal this game would add.