Can Microsoft legally ban a competitor for percieved incompetence? I doubt it . partiuclarly seeing how much competence is shown with windows and MS teams software
Microsoft assigns driver levels to these guys etc. and allows them to load kernel mode components as protected etc.. If they do not allow that - CS cannot cause such damages. ofcourse, as you pointed out, this will then turn into some lawsuit blaming MS for killing competitors, even if they do it to try and protect their customers.