Are there no legal recourse options for breaking the license so blatantly?
No, GPL FAQ specifically addresses internal distribution: https://www.gnu.org/licenses/gpl-faq.html#InternalDistributi...
> Is making and using multiple copies within one organization or company “distribution”?
> No, in that case the organization is just making the copies for itself. As a consequence, a company or other organization can develop a modified version and install that version through its own facilities, without giving the staff permission to release that modified version to outsiders.
> However, when the organization transfers copies to other organizations or individuals, that is distribution. In particular, providing copies to contractors for use off-site is distribution.
Please consult sources before making a strong statement.
Which couldn't be more irrelevant, because
a) This software doesn't appear to be licensed under the GPL.
b) The question here is not whether or not it's distribution, it's if it's copyright infringement. Making copies of copyrighted material is illegal (up to fair use and licenses) regardless of whether or not you distribute them.
c) The GPL also requires you maintain the license header when you are making copies (GPLv2 term 1, "You may copy [...] the Program's source code as you receive it [...] provided that you [...] keep intact all the notices that refer to this License [...]" (other terms and conditions do apply, hence the ...'s).
d) The license (and the law, and court rulings) is the source material, not GNU's not legally binding faq.
> Does the GPL require that source code of modified versions be posted to the public?
> The GPL does not require you to release your modified version, or any part of it. You are free to make modifications and use them privately, without ever releasing them. This applies to organizations (including companies), too; an organization can make a modified version and use it internally without ever releasing it outside the organization.
You're not free to make copies without the license. You are free to make copies with the license, because that's what the license granted you permission to do. You aren't free to do so without preserving the license, because you don't have a license to do that and that's copyright infringement.
You aren't required to publicly release derivative works or their source, simply because the license grants you the ability to produce derivative works (provided you keep the copyright information intact) without publicly releasing them. You are required to keep the copyright information intact, because the license does not grant you permission to produce derivative works if you do not.
The requirement to keep the copyright information attached is simply not connected to your choice to distribute it or not. It's a requirement any time you make a copy or make a derivative work, even if you're only making that copy or derivative work for yourself.
I still control all 1000 computers, but I'm doing something I fundamentally cannot do with a single copy.
The question is a bit murky, not because it's unclear I'm making copies, but because some copying is fair use. For example to execute a program I need to copy it from the hard drive to ram, and (pieces of it) from the ram to the CPU. That's generally considered to be legal, despite being copying, approximately because it's necessary to use the program. The exact line here is not well defined.
(Also not a lawyer, just a nerd)
If you can prove it's your invention, and they're distributing it without your permission, they won't want to waste money defending a suit.
You may be a little guy, without enough dosh to launch a suit; but you could sell your interest to $COPYRIGHT_TROLL, then they'd be in trouble. So just ask them nicely to propose a settlement.
It's not like war, or anything; tech-company legal departments are there for just this kind of thing. Unless there are arseholes involved, it can all be friendly and business-like.