Considering that Free Software predates Open Source, and many popular OSI-approved licenses also predate Open Source, how can you justify your core claim upthread:

> The people that see open source code and assume that it is being developed collaboratively are not being unreasonable – that’s the purpose of the open source movement. If that’s an inaccurate assumption for your software, then that’s fine – but it’s you that is breaking social norms, not them.

It sounds like you think anyone who selects an OSI-approved license, and makes the code publicly available, is somehow explicitly opting-in to the Open Source movement, and users should "reasonably" expect collaborative development as the default. Is that accurate? Because it seems completely nonsensical to me, especially considering the licenses predate the movement.

When you come across a random project using an OSI-approved license, there's no way to know the developers' motivations for selecting that license, if they haven't explicitly stated it. Your default seems to be an assumption that they're opting in to the "open source movement" and all of the social norms that you wrap up in that, but your assumption can be completely wrong, and that doesn't mean the developers are "breaking social norms" of a movement that they never subscribed to in the first place!