Is it possible to disable a specific extension in Visual Studio from the command line instead of starting Visual Studio manually and disabling it from tools?
As a supplement,
Command Line cannot disable one installed vs extension and Command Line can only do install or uninstall related operations.
The disable operation is only for VS IDE. In fact, vs extensions itself is designed to be used in the IDE, not the command line. Therefore, only the IDE can get the full functionality to manipulate it.
The VSIXInstaller.exe is a big step taken by Microsoft and the command line operation itself has limitations and room for improvement. But that disable the extension cannot be obtained under Command Line so far.
If you are comfortable uninstalling this particular plugin, you can try Drew's suggestions. If you still want disable it rather than uninstall it, you have to open VS IDE and then click disable option for it.
Or you could suggest a feature on our DC Forum. When you finish it, you could share the link here and anyone who is interested in it including us will vote it so that it will get more attention from Microsoft.