This isn’t bickering. These definitions have existed for literal decades. There are multiple models for making source code available, and people can choose what license they want. But this isn’t open source. This is source available, free (as in beer, kinda) license.
You don’t have to pay, and you can see the source code. But, in my quick reading, I don’t think you can make modifications, distribute modifications, distribute unmodified versions, and there is a restriction on how you use the software (non-commercial only).
This is the same type of license Microsoft gave certain large (TLA) customers for Windows, IIRC. I believe they called it “shared source,” as in they shared a copy of the source with you, but you couldn’t use the source for more than review. No one would claim that was open source.
There are differences between free, open, and available. This is only the later. No one cares about what license something is available through. Authors get to do whatever they want. People only care when you try to claim one thing, but it is really something else. In this case, the company is trying to use the term “open source” as a selling point of their software, when it isn’t. This license doesn’t even match the definitions they use on their own site!
I’m happy the authors want to make it possible to audit their software. That’s a laudable goal. If they want to restrict usage of the source code to non-commercial use, that’s fine and up to them. Just don’t call it “open source”.
Just because something is free doesn’t make it open. And just because something is open doesn’t make it free (as in freedom or beer). Similarly, just because something auditable and available, doesn’t make it free or open.
The fact that the authors don’t know the difference (or are potentially misrepresenting the difference) will only make the community mad - especially the part of the community that would care about seeing the source code in the first place. If they instead were marketing the project as “source available” for auditing or non-commercial use, this wouldn’t have been an issue.