I personally don't have a problem with
any license. I think Free and Open Source software is important, though, and this is not it. The problem here is not the fact that there is a license that allows licencees to view source code. The problem is that this organisation wishes to replace open source software with their view.
(Note: I'm not going to talk about software freedom here, which is a subtly different perspective. I just want to talk about open source). The idea behind open source is that when I decide to use the software, I am not locked in to a single vendor. Not only do I have access to the source code, but I have permission to modify it and distribute it for any reason that I want.
It's that advance permission for modification and distribution that de-risks your project. If, in the future, I want to do something differently than the original author, I can. For example, imagine that I tie my infrastructure in to version 2 of the software, but they release version 3, removing most of the functionality that I depend on. I want to use version 2 and backport security changes from version 3 into version 2. Similarly, I want to distribute my changes so that anybody else that's in the same boat can pitch in on the backporting effort.
So, as an author, you give up some control of the ultimate destiny of your code. There are some advantages as well, though. If your customers take advantage of their ability to add features of their own choosing, you have turned customers into collaborators. In that way, you have a kind of consortium effect. However, you are in a privileged position, because you still own all the trademarks wrt to the project. So even if someone starts to compete against you, they can't piggy back on your marketing and sales efforts. Not only that, but if you choose a copy-left style license, they can't effectively compete unfairly against you because all of their modifications are also usable by you.
So it's a kind of balancing act. You get this low barrier of entry for participation of your customers and they get a substantially de-risked product.
There are lots and lots of licenses out there which permit the viewing of source code. It has been very popular with game engines for a long time now. Microsoft made the attempt (now abandoned, I think) of have the "Shared Source" license. Even back before free and open source was a thing, source code was often available, though there was no explicit license to use it.
This is not a "better" open source. It is objectively much worse at fulfilling the goals of open source software. Like I said, I don't care if they want to use licenses like that. I won't use their software, nor will I recommend that people accept a license like that. But I don't have a problem with them existing. I do have a problem with them pretending that what they have is an improvement on free and open source software.