I'm not here to say it _should_ be open. Instead, I'm saying they offer a valuable, international (global) service and I want their economics to be sustainable, and have personally no objections to them keeping their AI models private if they wish so.
Meanwhile, the whole idea of iNaturalist has evolved around voluntary reporting, community involvement, and open data, and I think some of that needs to stay. They can't turn fully commercial.
I think the problem for me here is that previous you mentioned yourself that the primary funders are nonprofits and government organizations (NSF, Nat Geo Society, Gordon & Betty), so it doesn't seem like even you believe the private commercial piece of the puzzle is very large. I doubt allowing the models to be open would sabotage the work they do with any of the aforementioned organizations, or hurt their ability to target future government/non-profits.
If in fact what you said is true about the sources of funding, it would then seem that the US taxpayers (the relevant party here) are footing a large part of the bill from direct and indirect subsidies. I feel that it can be reasonably argued that a non-profit organization that is benefiting from significant public subsidy should make their model available for public use.
Meanwhile, the whole idea of iNaturalist has evolved around voluntary reporting, community involvement, and open data, and I think some of that needs to stay. They can't turn fully commercial.