Let me split this into some points:
1. Underground Gaming is already a thing. It is for sure. There are countless of underground devs around - the problem is: Even if you try, it is damn hard to find them. And we can hardly find each other. This is something I want to change.
2. I say nowhere that Indie is pejorative, neither do I say that it is only tech demos and low effort. But those are there, and make it hard to stand out. The places were it is possible to stand out are dominated by (semi-) professional developed games.
3. I don't think of freeware or donationware. In fact I see a wide range of variants for "noncommercial", and I would like to have a discussion what kind of "noncommercial" is "noncommercial" enough for underground gaming.
4. This serves the purpose of allowing those who enjoy to develop and to play underground games to connect, exchange, find each other and to collaborate.
Most of these questions are - in my opinion - answered in more detail in the texts I linked. Maybe you'd to read those? If not: I don't mind answering further questions :).