Since the ethical concerns about potential sponsors should be considered on a case-by-case basis, it seems like the most relevant aspect of such a policy would be the process by which the sponsors are approved. The ASF Sponsorship policy explicitly avoids having such a process:
Because The Apache Software Foundation Sponsorship Program needs to apply its policies quickly, fairly and equally, without the need for exceptions or board votes, we have tried to maintain this document at the most basic level. However, the Foundation reserves the right to decline any sponsor without providing a reason and at our sole discretion.
For a different example, the Association for Computing Machinery Conference on Fairness, Accountability and Transparency has a sponsorship policy that includes a clear process for Sponsorship Approvals: ACM FAccT - 2022 Sponsorship Policy
In short, to ensure conference sponsorships advance the FAccT principles, everyone on the steering committee for the conference has a say over whether a sponsor is accepted and the policy outlines a clear process for the necessary notifications and decision-making.