Linus’ thread: (CW: bigotry and racism in the comments) https://social.kernel.org/notice/AWSXomDbvdxKgOxVAm (you need to scroll down, i can’t seem to link to the comment in the screenshot)
“Based” is typically used to describe someone who says/does something without caring if they’ll be judged for it. Most commonly, it’s shorthand for “That’s a controversial opinion and you are bold for saying it, but I agree with you.” It turns the previous sentence into an adjective, which is a little weird but it makes sense eventually.
So if I had to choose a single word as a synonym, I would say “Bold”.