Because these bodies want to maintain a moat for the products made by member companies. No more, no less.
A great example of this is the GigE Vision/GenICam standards that are used by basically all machine vision cameras, which were accessible to non-licensees but not usefully implementable (these standards explicitly prohibited their use in implementing any open source implementation of the standards). So essentially all they could be used for were (1) as a licensee producing closed-source software for their own cameras, or (2) you as customer trying to complain to your camera/software vendor that they failed to implement some part of the standard correctly.
> these standards explicitly prohibited their use in implementing any open source implementation of the standards
Is that legally enforceable? IANAL, but that feels dubious to me. Feels like there should be a way around that.
If you make a thing and copyright it, you get to dictate terms. But the legal alternative would be a clean room implementation. The implementation team never saw the standard, so it's not being used.
Yeah, clean room implementation is the only way - and the route chosen by the aravis project that builds a FOSS implementation (which is a really great piece of software, way nicer to work with and easier to debug than the terrible vendor SDKs).
probably enforceable via patents.
This even extends to how some standards are written: deliberately complex and poor work just to make it frustrating and ensure a high barrier of entry. And of course there are either no test suites or testing against them costs a fortune.
This is the kind of thing politicians in a reasonable world would make illegal and subject to sanctions.