The text you quoted is purely about copyright/licensing, not about the maintainers' sanity.
The more relevant quote is: "In order to keep SQLite completely free and unencumbered by copyright, the project does not accept patches from random people on the internet. There is a process to get a patch accepted, but that process is involved and for smaller changes is not normally worth the effort." Though this is still about copyright, not about being swamped with PRs.
The more relevant quote is: "In order to keep SQLite completely free and unencumbered by copyright, the project does not accept patches from random people on the internet. There is a process to get a patch accepted, but that process is involved and for smaller changes is not normally worth the effort." Though this is still about copyright, not about being swamped with PRs.