The article clarifies that scenario:

"However, if your organization has returned to in-person work, but you choose to work from home, it's less likely that your business expenses will be seen as "necessary"—as you could have avoided them by working from the office or other worksite."

California regulations aside, my understanding is that's sort of the tax code today. My accountant always told me that home office expenses were a questionable deduction if you had an office to go into if you wanted to.