VSCode on the other hand looks open source, they claim it's open source, the extension is open source, yet the most critical component is not. I would call this the new new Microsoft - we look like we love open source, we give you open source tools, but it's either not open actually (this) / will not work if you compile it yourself (VS Code and .NET debugger) / only works on Windows ("Multi-platform App UI", maybe Mac, I don't know)
If python removed a feature so a specific IDE could have it exclusively I think people would also be upset.
People get angry when suffocate existing tools with their free and "open source looking" alternatives. Ask Python devs if they think that their VSCode extension is open ... Even I thought it was open yesterday, turns out it's not and they pretty much removed support Jedi, the acutally open language server.
for example, Sublime never did that, sublime was closed, and is closed, and will be closed.
They arn't trying to gain traction at the cost of lying in their advertising and labeling, they don't exclusively release closed licensed versions of their "open-source" product like MS does