Yes it is, or it's intended to mean the same thing, and that essay you linked to acknowledges several times that it's the same thing (or nearly the same thing).
Open source and free software are kind of like climate change and global warming: two terms that refer to almost the same thing but have different political slants.
The reason I insist so much upon this is that I want people to remember that in order to qualify as "open source" it must provide the same freedoms as free software. How and why it provides those freedoms is a matter of philosophical differences, but in the end results in nearly the same set of free and open source licenses. It is very rare and unusual for the OSI and the FSF to disagree on licenses.
Although the licenses and in some cases even the software is the same, the communities are very different.
The Open Source community is creating high quality technology for techies to build great things.
The Free Software community is trying to protect end-user rights.
Those are very, very different things. Both have value, and they often overlap, but claiming they are the same is in my opinion quite disrespectful to the motivations of the people doing the work.
Free Software advocates will as a result tend to prefer copyleft style licenses that protect users, while Open Source people usually prefer liberal "business friendly" licenses that let them do whatever they like with the technology - including creating proprietary cloud-based or closed-source products (which deny the end-user rights the Free Software folks want to protect).
(edited slightly for clarification and to be less judgemental)
Yes it is, or it's intended to mean the same thing, and that essay you linked to acknowledges several times that it's the same thing (or nearly the same thing).
Open source and free software are kind of like climate change and global warming: two terms that refer to almost the same thing but have different political slants.
http://jordi.inversethought.com/blog/5-things-we-have-forgot...
The reason I insist so much upon this is that I want people to remember that in order to qualify as "open source" it must provide the same freedoms as free software. How and why it provides those freedoms is a matter of philosophical differences, but in the end results in nearly the same set of free and open source licenses. It is very rare and unusual for the OSI and the FSF to disagree on licenses.