Half the time it’s because it’s FOSS with a proprietary skin over it.

I make all my sucky code public because I’ve never seen a codebase that doesn’t suck in some way

Asshole take: if you share your project online but not the source code I immediately think your code sucks.

Let’s be real your clone project is not something a venture capitalist is going to invest in, there’s literally no reason to hide it but shame. Shame of sinful and bad code.

On the other side there’s people that genuinely use that as an excuse and say “they’ll open source after they cleaned up the code”. Why they couldn’t clean it up in the clear is beyond me, no one will shame you for your code, just sharing it under a free license is admirable in and of itself