I agree, lots of false statements here. "Code - OSS" is open source, and released under the MIT license. Visual Studio Code is built by combining "Code - OSS" with proprietary code, and is released under the following non-open-source license:
https://code.visualstudio.com/licenseFrom their github repo:
Visual Studio Code is a distribution of the
Code - OSS repository with Microsoft-specific
customizations released under a traditional
Microsoft product license.
"Visual Studio Code" is to "Code - OSS" what Google Chrome is to Chromium. Microsoft has just been successful at tricking people into thinking that Visual Studio Code is itself open source through misleading marketing on their website and things like naming the github repository for "microsoft/vscode".