Maintainers are well within their rights to say "Fork it" if your vision of the product isn't theirs, or it would add time to their releases, or for no reason at all. One of my favorite examples is https://www.jwz.org/blog/2016/04/i-would-like-debian-to-stop... . Supporting a platform is expensive in time and mental energy. PlatformIO is under no requirement to do so.

From what I can gather, PlatformIO is not willing to fund future development on RPI themselves, and reached out to the much better capitalized RPI foundation to try to get funding. They may or may not have been assholes in how they did that, we'll probably never know. Asking wasn't insane, rejecting the patch isn't... Insane per se, even if it's probably shooting themselves in the foot by denying themselves a huge customer base. Their communication has been poor as heck, though.

I am intentionally not warning about JWZs policy on links from HN, because it's funny to me.