Red flag if job lists MS Office as required experience?

I see a lot of software engineer jobs that list experience with the Microsoft Office suite as a requirement.

First of all, who puts that in the job description? I can't imagine an engineer doing it, but then the rest of the job description often lists things that clearly an engineer did put there, like "experience with REST APIs, solid understanding of design patterns...". Does this happen when HR decides to "improve" the job description that the engineers wrote?

Second of all, is this as bad of a red flag as I'm thinking, or am I overreacting?

EDIT: People seem to be misunderstanding my question. I'm not asking if it's a red flag that they expect people to know how to use MS Office; I know everyone uses Office-type software in their job. I'm asking if it's a red flag that they thought it was important to list MS office as required experience.