The key part there is that they're not paid. So working on a passion project is all that matters.
No, it isn’t. That’s not how it worked on the playground as little kids and it isn’t how it works in the open source community.
Think of it like this: if you’re playing by yourself in your own personal sandbox in the back yard of your house, you’re free to do whatever you want with the sandcastles you build. But, as soon as you invite all the neighbourhood kids to join you, it doesn’t matter if you built the biggest sandcastle before anyone else arrived: you’re now in a social environment where social rules and etiquette apply.
If the other kids politely critique the sandcastle and suggest improvements that you don’t agree with (or don’t think are important), then you’re faced with a dilemma: either compromise and work out a way forward that’s satisfactory (if not perfect) for everyone, or ignore them and face a potential breakup of the community as well as the ostracism which tends to follow. Even worse is something like deciding “no, this is my sandbox, everybody get out!”
Now, if you’ve got the foresight to post a sign by the sandbox which lays out all the rules and expectations for participation, then you have a lot better chance of getting everything to work out. But the idea that “this is my passion project” trumps everything else is not gonna fly in basically any community above a handful of people.