So I did read them but there is a lot to paraphrase without tipping into 2000 words so I will try to be succimct.
1) The steps you point out to the searchabilty problem is "use this hashtag" and "use the collection I created" so use itch the same way everyone else uses it. I think we need an external way to browse by using the API because itch struggles with discoverability.
2) I pointed out you where using it pejoratively becaise multiple sections are dedicated to possible pitfalls in indie gaming which would be replicated in underground gaming unless you intend to police which games can remain underground.
3) the various noncomercial examples are the ones offered by itch and similar platforms already. Us in the Pen and Paper space already do free, suggested donation, alternate builds, free SRD with but profit on print copies, print copies at cost but make money from digital sales. We even trade games as suggested, using the existing promo code infrastructure.
4) So what is "this" because as stated underground exists (completely unsigned), the pay models exists, game makers see games as art, the distribution exists, the discoverability exists although I would pay you to imprive it... all that does not exist is a cop to tell us if we are doing underground correctly.
It feels like a manifesto declaring what a taco is, or what punk is, or what is good taste... even the best authority on the subject only has one perspective and it cannot be applied retroactively to 50(?) years of underground games.