> The package repository isn't preventing the developers from continuing to publish their packages elsewhere
You are right that the package index doesn't owe developers anything and this is in fact something I called out explicitly in the post. However I believe your point about "isn't preventing" is not quite accurate. In order to participate in dependency trees in most ecosystems you need to be on "the" index. Yes, you can sort of create dependencies to stuff off PyPI but this breaks down really quickly. Because of this PyPI has a special role to play.
This is not too dissimilar to discussions we are having about freedom of speech and similar things at the moment and I think the answers are much more nuanced and complex than it might look on the surface. If PyPI were to start putting restrictions on some people publishing or accessing packages, we had a much bigger challenge on our hand. To be clear: this discussion is not about that, but the "just move somewhere else" type of answer I do not believe is a good option to dissatisfaction with the primary index.