Can you extrapolate a bit? Why is GOG an undesirable platform to be on, especially as you seem to be fine with DRM-free releases elsewhere (which is awesome, btw)
Finally, thank you for SpaceChem! Still great, even after all these years
My understanding is that GOG is not necessarily undesirable, but they are very selective: Unlike Steam or Itch, you have to convince them that it's worth their while to sell your game. And their choices of what (not) to sell are not infrequently baffling. Lots of developers have gotten burned by that, including Zachtronics
I have a hard time believing that GOG rejected a Zachtronics game. They're popular, high quality, and a good match for the GOG audience. An GOG already sells several of them (I own SHENZHEN I/O and Spacechem on GOG).
I'm not quite sure what the expectations of semi-privacy are here, but he's talked about it on the TC Discord, in the #development-branch-feedback channel (a search for 'unprofessional' should find it).
https://astralogicalgames.itch.io/kaizen-a-factory-story