I was unaware that the secretary of defence was a combat role?

He (and his allies) have referred to him as "warfighter": https://www.radiofree.org/2025/04/23/look-ma-im-a-warfighter...

In that context he is clearly referring to his previous combat roles on the ground in Iraq.

It would be like a barista becoming CEO of Starbucks and saying, "the employees are happy to have a barista as CEO."