No. Microsoft is not liable, at least when it applies to HIPAA.

The HIPAA Rules apply to covered entities and business associates.

Individuals, organizations, and agencies that meet the definition of a covered entity under HIPAA must comply with the Rules' requirements to protect the privacy and security of health information and must provide individuals with certain rights with respect to their health information. If a covered entity engages a business associate to help it carry out its health care activities and functions, the covered entity must have a written business associate contract or other arrangement with the business associate that establishes specifically what the business associate has been engaged to do and requires the business associate to comply with the Rules’ requirements to protect the privacy and security of protected health information. In addition to these contractual obligations, business associates are directly liable for compliance with certain provisions of the HIPAA Rules.

If an entity does not meet the definition of a covered entity or business associate, it does not have to comply with the HIPAA Rules. See definitions of “business associate” and “covered entity” at 45 CFR 160.103.

https://www.hhs.gov/hipaa/for-professionals/covered-entities/index.html