at least one incident they didn't want their masterpiece used with certain other mods.
The egos on some of these people...
If you're making a mod, it's not yours. "You didn't build that". You took someone else's work, namely Mojang/Microsoft, and you edited it to your liking, using tools and resources given to you for free from a community that you then have the chance to give back to. You can contribute to the community, or go design your own game from scratch.
I have absolutely nothing but contempt for anyone who builds a mod then pulls it from the community for something like this. This is a great way you can learn some basic design principles for free, and you're then free to take those principles and apply them to a real project of your design. It's a really great place to practice. And you pay for that place simply by sharing your creation with the rest of the community that made it possible.