Your argument would apply to any Apache or BSD licensed code. Not just Caddy.
Caddy has used the Apache 2 license for 2 years. Why would you not contribute now vs when the license was committed? Because they are not providing full free builds anymore? The public source code you are contributing to is still free. Nothing would have stopped anyone else from slapping a EULA on a custom Caddy build to sell.
It feels like a poor reason to refuse to contribute to an Apache licensed project.