I know your reasoning is I should make a new library because X and Y don't exist in the existing ones. But really what most people think of is why not just send a pull request to the existing ones with that new functionality?
Maybe he just wants to build his own thing, or he doesn't like the code from the existing ones, or he doesn't want to commit to learn and write the code just to have his PR ignored or rejected, or he doesn't want to wait until someone notices his work and decides to ship it into the next version.