The majority of open source software doesn't make sense to be used via a docker image and the definition for open source needs more than just source code access

You may find this pedantic but it really is an important distinction. I've had licensed access to source code that was not open source and very restrictive through various jobs in the past (not talking about code I worked on but business agreements that included access to source code for audits and stuff)

Having access to the source code does not necessarily give access to use, share, modify. The two biggest requirements for open source beyond just the actual source code is the ability to modify and redistribute. Source-available software is NOT good enough