I disagree. They said open source, so I’ll take them at their word that they mean open source. If they meant otherwise, they should’ve said that instead.
This is a highly nitpicky topic where terms have important meanings. If we toss that out, it becomes impossible to discuss it.
I've linked elsewhere to the Hippocratic License, which freely refers to itself as open source while specifically being built around refusing licensing based on ethical considerations. OSI don't own the term open source, and the simple and plain meaning of the term is clear to see. Otherwise, we wouldn't consider GPL software to be open source, because it attaches conditions on usage. That even applies to non-copyleft licenses like MIT which demand author attribution. The term open source is best read literally unless someone says "I want an OSI approved license".
The GPL places no restrictions on how you can run the software. All meaningful licenses place restrictions — or, conversely, limit the permissions they grant — on how the code can be used, distributed, integrated with other projects, etc.
But I disagree that the meaning of Open Source is malleable. As others here said, if we want to make a new definition, we should make a new term. In my opinion, in this case, we have. It’s Source Available, which is basically “look, but don’t touch”. And as with other brightly colored things in nature, it’s generally best to avoid it.
The OSD came out within months of the phrase "open source" first being used, and the phrase was coined as part of the same process of discussion that produced the OSD. It's not a natural phrase and does not have an obvious "simple and plain meaning". It's a term of art.
This is a highly nitpicky topic where terms have important meanings. If we toss that out, it becomes impossible to discuss it.