We cannot tell volunteers to not do something (i.e help Microsoft) in the same way we cannot tell volunteers to do something.
And if FFmpeg was so passionate to get a support contract from Microsoft, that should have been a requirement first before they provided the support.
Once again, FFmpeg set their own rules. First with free software and now with free support.
Life lesson: Don’t provide free software and free support, and then complain about your own doing.