[Crabber]

"open source" and "free software" are two words for the exact same thing.

Both of them are pretty poor descriptors. "open source" doesn't convey the legal freedom you are granted (as you have just found out), and "free software" makes it sound like it's just about price.

If someone lets you see source code but doesn't allow you to do anything with that code it's not what people would call "open source", you could probably call it source-available or something. "open source" has a specific legal definition that means code released with a permissive license.