Well. What I wrote was (from what I heard) the original reason for the copyright assignment requirement. However, since a few years ago, the FSF does not requ

Well. What I wrote was (from what I heard) the original reason for the copyright assignment requirement. However, since a few years ago, the FSF does not require GNU projects to have copyright assignment anymore. The FSF leaves the choice up to the individual project maintainers, which would, one assumes, drop the requirement if it affected developers and contributions for their project. Some have indeed dropped it, some have not.