> The work, Inspeqtor which is hosted at GitHub, is far from a “clean-room” implementation. This is basically a rewrite of Monit in Go, even using the same configuration language that is used in Monit, verbatim.
There is no concept of "clean room" in copyright law, the only issue is whether or not substantial copying has occurred. While it may be easier for the author to avoid accidental copying if he has never looked at the Monit source code, having seen it, being inspired by its design, or deliberately building a compatible system do not constitute copying. The notion that it must be copying simply because it uses the same configuration language is without merit, due to the fact that the configuration language itself is not a creative work and is not eligible for copyright protection, in the same way that an API or a programming language is not eligible for such protection: it is a medium for expression, not an expression in itself - otherwise all programs written in a given programming language would be a derivative work!
I suspect that it is this misunderstanding that has led the authors of Monit to file this DMCA takedown, and that they have acted in good faith, but with an insufficient understanding of the limits of what copyright protects.
> a. [private] himself admits that Inspeqtor is "heavily influenced“ by Monit
Being heavily influenced is not the same as copying. OpenOffice Writer is heavily influenced by Microsoft Word, and can even open the same file format, but it does not copy any of Microsoft's source code.
> b. This tweet by [private] demonstrate intent. "OSS nerds: redesign and build monit in Go. Sell it commercially. Make $$$$. I will be your first customer.”
The quote was "redesign and build Monit in Go" which does not show intent to engage in substantial copying of Monit's source code. If anything, it suggests an intent to write a new, redesigned system with its own source code but compatibility with monit.
Without looking at the source code, it's hard to say more, if the author simply ported the source code of Monit to Go then it would certainly be a derived work, but the DMCA claim doesn't mention any such copying. It's important to remember that compatibility is not copying and that only the source code to a computer program is covered by copyright - its architecture, design, and even APIs (see Oracle vs Google) are not protected by copyright, because otherwise the copyright claim would effectively behave like a patent, preventing anybody else from creating something conceptually similar.