The person who created the MCP was hired by Mojang several years ago.

That person still releases the MCP with Mojang's blessing last I checked.

That doesn't change the fact that Mojang didn't make MCP. If Searge didn't step up and do it there's no reason to believe that Mojang ever would have come up with something similar. Mojang promised for years and years that "the modding API will be released any time now" yet they haven't done anything to materially support the modding community other than to hire Searge and the Bukkit team.

I guess they finally have behavior packs like resource packs for Bedrock edition (used to be Minecraft PE) but that doesn't allow you to write any kind of turing complete code for custom behaviors. That's the closest they've come and all that lets you do is stuff like make pigs behave like a creeper and explode when the player gets too close.

To date it has been 8 YEARS literally the better part of a decade from when Mojang first announced that they were going to release a modding API and they still haven't done anything. Releasing these two libraries as open source is a nice gesture but that doesn't actually do anything for the modding community. The least they could do is just stop obfuscating their releases so that MCP isn't stuck doing a bunch of unnecessary work.