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Not a Criterion: Political Activities
As discussed here, revoking a degree based on political activities (e.g., criticizing the university that granted the degree) would gather wide attention, but we are not aware of any such cases having happened. Although anything could happen in the future, given the lack of observed cases it does not seem political activity is considered grounds for revoking (non-honorary) degrees.
Indeed, taking any sort of action based on political expression is anathema to Western ideas of tertiary education.