My psychotherapist said something along those same lines but it was in order to force me to answer the question why is it a problem.
For me, in my life, I have always "worked" during the day in an easily distractible state and without being able to commit effort to anything substantial or focus. I self-medicated with caffeine to get anything resembling focus and did all of my actual daily tasks in a 3hr window when I got home and worked into the late evening. Usually with a massive sense of guilt about how I didn't really do anything during the day.
This was ADHD, I could not control when or how I focused. It gets worse with open office environments, but that's not the cause. I have an issue with executive function and delayed gratification. I do not have the ability fundamentally (even when motivated!) to task my brain with working.
But I can hold down a job and have done so for 16 years at this point and I am very successful in my career. That is not a good judge, you work around your issues if you have them- in my case I just don't have anything resembling a life outside of work in order to paper over my executive function disorders.
It took me 11 semesters (plus two summer terms) to finish my undergrad with a low C grade average. Prior to kids, I would get to work between 7 and 8. If I was having trouble focusing that day, I'd leave between 4 and 5pm. If I was having a good day for focus, I'd stay as late as 10pm. Two "good days" in a week would put me at over 20 productive hours, which is a pretty solid foundation for being at least in the "not fired" category. If I didn't have two "good days," well that's what the weekends are for.
Reading the above, I think I understand why "burn out" is mentioned in TFA as something ADHD can lead to...
But those compensation mechanisms eventually stop working and I guarantee that persons life outside of their job is a complete dumpster fire.
There's a good chance that much of the ADHD behavior is being written off, eg. as a moral failing, when it's really a disorder that's really harmful to the person.