People being able to adapt their software to their own needs by making changes to the code is exactly what open source is about. This is good.
What is a problem though, is to have the code merged in the main repository requires you to gift them the rights to your code (not just license it). They are also not very clear about this in the summary of their CLA: “You're giving Zed permission to use and share your contributions (like original works or modifications).” which could be misunderstood to just be a usual open source licensing agreement, but seems to be complete handover of copyright: https://zed.dev/cla
This is not good, and something people should be more aware of when contributing.