Because if they don't allow these kinds of code contributions, and wait until products are shipping to accept code, upstream Linux will be a year or more behind

Because if they don't allow these kinds of code contributions, and wait until products are shipping to accept code, upstream Linux will be a year or more behind when new chips get shipped, and users will have to run out-of-tree forks of questionable quality. And in this case, the now-useless crap is being removed from the kernel.