Before you argue that ReactOS is merely a free implementation of Win32 API, let me clarify: if the purpose of ReactOS isn't to run some Windows-only software S, then what is the purpose of ReactOS? if S was free, it wouldn't be Windows-only as it would have ported to free OS's.
I don't object to implementing free software to support APIs that users use. There is a lot of non-free software written for the Lose32 API, but there is also a lot of private (unreleased) software which runs on that API. Thus, its use is not only for running proprietary software. I would ask the developers of platforms that run the Lose32 API to tell the users that running proprietary Windows apps is not freedom.