I assume that by "this process" you mean the Eclipse IP Due Diligence Process.
The short answer is that the Eclipse IP Policy requires it and the Eclipse Board of Directors requires that Eclipse Projects conform to the Eclipse IP Policy.
You're right. We do more than Apache does. FWIW, we regularly feed issues that we discover back to Apache projects.
I'll argue that--at least in the general case--the "legal status of both licenses and their inclusion" is not universally well-understood. At least in part, the Eclipse IP Process exists so that software developers don't have to think about all the nitty-gritty nuances of licenses and such.
Regardless, our policy requires that we have confidence that content is licensed correctly. We do frequently find, for example, content that is not clearly licensed or may have a different license on some files. Basically, we don't necessarily trust that the declared license for third-party content matches the actual content. This is why we set up "Type A" Due Diligence for third party content to require the use of a tool (the tools allows us to process things more quickly than can be done manually, with generally high confidence in the results).
Capturing it all in CQs in IPZilla satisfies our accounting requirement.
During more thorough review (which we do for all project code and "Type B" third party content due diligence), we validate that the provenance of the content is known, past relicensing exercises are valid, and all sorts of other things. Again, the IP Team regularly finds anomalies that run counter to the declared license.
The basic idea is to reduce the legal risk associated with adoption/consumption of the software.
I spent a little time looking through our documents for a simple statement that might serve as a response, but didn't find one (It's late and I may just have not found it because I'm pretty tired). This seems like an obvious addition for the
Legal FAQ or
Committer Due Diligence Guidelines document. I'll make sure that we add something.
Wayne