They're referencing what the second protester (Vaniya Agrawal) mentioned in her email:

Know that Microsoft’s human rights statement prohibits retaliation against anyone who raises a human rights-related concern: Human rights statement | Microsoft CSR

The Microsoft Global Human Rights Statement has a "Foundational principles" section that says:

Our commitment to human rights defenders: Our commitment to respecting and advancing human rights includes respect and support for the work of human rights defenders around the world. Human rights defenders are people who, individually or with others, engage in activities and advocacy that contribute to the protection of human rights and the rule of law, good governance, tolerance, and diversity and inclusion. Human rights defenders face persistent physical, social, economic, and psychological threats. Microsoft does not tolerate threats, intimidation, retaliation, physical, legal or cyber-attacks against human rights defenders. This commitment extends to all human rights defenders, including those working on issues related to Microsoft and those exercising their rights of freedom of expression, association, and peaceful assembly, including to challenge or protest aspects of our own business.

Microsoft is clearly declining to fulfill its commitment as it is written in its statement.