This led me down a rabbit hole and just now I realized Wikipedia is open source [0], not sure if I'm the only one who didn't know that, but there it goes. Of course, I was aware that the framework they use is open-source [1] and developed by them, just didn't know the website itself was too.
By your same logic, is social media open source as you can post comments on the posts of others? Is the level editor for popular games open source? Of course not. The ability to edit a page is not any kind of indicator of license.
This led me down a rabbit hole and just now I realized Wikipedia is open source [0], not sure if I'm the only one who didn't know that, but there it goes. Of course, I was aware that the framework they use is open-source [1] and developed by them, just didn't know the website itself was too.
[0]: https://gerrit.wikimedia.org/r/c/wikimedia/portals/+/908683
[1]: https://www.mediawiki.org/wiki/MediaWiki