License can not order someone to publish something. They may not have a rights to publish code, or it was created as part of employment...
I'm not however convinced they are really in violation by calling a binary plugin. GPL itself does not forbid you from dynamically linking to or calling unrelated software. The network plugin is analogous to a device driver, it's not core part of the slicer.
GPL differentiates between a "Combined Work" and an "Aggregate":
> A compilation of a covered work with other separate and independent works, which are not by their nature extensions of the covered work, and which are not combined with it such as to form a larger program, in or on a volume of a storage or distribution medium, is called an "aggregate" if the compilation and its resulting copyright are not used to limit the access or legal rights of the compilation's users beyond what the individual works permit. Inclusion of a covered work in an aggregate does not cause this License to apply to the other parts of the aggregate.
If they tried to add DRM to Bambu Studio and prevent you from replacing their blackbox with a different one then that would be where they would clearly go against the v3's TiVo provisions.
GPL does not contain the words "dynamically linking". That‘s just a common interpretation as a shortcut.
In this case there are arguments for the program-plugin communication to be "intimate" and as such falling under "derivative work". But it‘s easy to take the other side, as well.
GPL license in spirit is about assuring the user freedoms. No user freedoms are limited in this case. You are free to modify and redistribute the software as you like. OrcaSlicer pulls changes from Bambu without any issues.
I don't think trying to enforce the license in this way, even if possible (which again I think if it was it would happen with Linux drivers long before), is the right thing to do anyway. All it's doing is painting the GPL as a liability to any business for no benefit.
No it can't, you are right.
By default, you don't have any right to use any given software. The license outlines the conditions under which you have are permitted to use it. If you don't comply with the conditions, you aren't permitted to use it.
The license isn't ordering you to do anything, you can simply not use the software!
if I sign a contract saying I'll produce a million Iron Man action figures, but I don't have the IP for Iron Man, I can't just shrug my shoulders and say "well, you can't make me." the Court would make me pay damages.