The mainstream FOSS licenses (GPL, BSD, Apache2, etc.) are all included both in the official list of open source licenses [2] and the official list of free software licenses [3], so these licenses are both open source licenses and free software licenses. These lists might have some minor differences, but they share a substantial subset and the definitions broadly speaking define the same thing.
[0] https://opensource.org/osd/
[1] https://www.gnu.org/philosophy/free-sw.html
OSS as a term was created at a time when free software, as defined by GNU, was effectively becoming the de-facto standard for collaborative efforts on the internet. Yes, MIT and BSD were around (barely, in the BSD case), but the rising star was Linux and Linux (and the software built on it - GTK, gimp, etc) was GPL.
The industry needed a way to get on the action without touching the "communist" GPL, and that's why ESR's definition of "Open Source" was endorsed. Obviously they coopted all the existing bits they were ok with (i.e. all the ones that did not impose any extra burden on companies), that's why the definitions overlap substantially; but they are not the same thing. If they were, there would not have been any need to create a new definition for it.
which against, doesn't really makes sense.
Stallman has repeated over and over that the Free Software movement is not about communism (despite what communist people like to say).
Most likely, the industry needed a way to get people to submit improvements and patches (essentially doing Development, QA and support) for free without having to give a way the right to sell proprietary services.
The distinction between copyleft and non-copyleft licenses, e.g. GPL and BSD, is different from the distinction between open source and free software, which is mainly ideological. The GPL is a copyleft license but also an open source license, as you can see on the OSI website.
For maximum context, here is a quote from the board meeting minutes [0] where the OSI approved the Free Software Foundation's copyleft GPL license as an open source license in accordance with the Open Source Definition: "The Open Source Initiative is pleased to announce that, based on broad review and acceptance by both the Board and the community, it has confirmed that GPLv3 and LGPLv3 both conform to the Open Source Definition."
But if you take a look at the Free Software Foundation's list [0] of Free Software licenses, you will see that it lists both the CDDL and the MPL as Free Software according to the Free Software Definition.
So why should a new definition have been needed to allow these licenses when they are already allowed by the old definition? Maybe you could supply some of that context you were talking about?
> So why should a new definition have been needed to allow these licenses when they are already allowed by the old definition?
Maybe you should ask the founders of OSI? If their work was fundamentally pointless, why did they do it? Because it wasn't pointless, it was seen as necessary to be able to say "we are Good Guys, but not like them dirty GPL hippies".