This is part of the issue and one of the causes of the stigma. People who have biological and/or genetic particularities and are unable to follow regular sleep cycles should not be put in the same category as people who have regular circadian rhythm. This article is about biological factors so its safe to assume we are discussing about people with actual circadian disorders and not people who have bad habits.
"Circadian rhythm sleep disorders are characterized by a persistent or recurrent pattern of sleep disturbance (difficulty falling asleep or staying asleep and excessive sleepiness) due to alterations of the circadian timekeeping system and/or misalignment of the endogenous circadian rhythm and the external environment." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3523094/
Key part of this being "persistent or recurrent". In other words, people who have been struggling with this for a long time and have it reoccur after trying out different strategies.
Adding a distinction could help. Perhaps "voluntary night owl" vs "involuntary night owl".
> Key part of this being "persistent or recurrent".
The key part is that it's related to the circadian rhythm and time keeping. That it's persistent and recurrent doesn't in itself distinguish it from other sleep disorders that may cause delayed sleep schedule, such as sleep-onset insomnia, or "bad habits" as you call it.
> Adding a distinction could help. Perhaps "voluntary night owl" vs "involuntary night owl".
If you want to address people affected by e.g. DSPD, and not "night owls" in general, it is perhaps just better to simply address them as such.
I think for it to be a clinical problem, there needs to be a struggle. Like, in my particular case, I enjoy staying up late. The neighbors are quiet, my housemates are generally falling asleep, and I've got an hour or two to myself to knock something out or research something I find interesting. There's no struggle though; I found a job that lets me work an evening shift and I couldn't be happier with the state of things. I feel like if I needed to get up regularly very early in the morning, there would be an adjustment period and then I would equalize on a new normal.
That certainly fits the description of "night owl," but I don't think there's anything clinical about it. My particular manifestation is more of a lifestyle choice, and based on what I observe in the tech field I'm hardly alone in making this choice. Folks who do have a sleeping disorder causing night owl tendencies to manifest (especially when they'd prefer, socially, to rise early) are in a different boat altogether, and I'm... honestly not qualified to classify them. It's an interesting space.
"Circadian rhythm sleep disorders are characterized by a persistent or recurrent pattern of sleep disturbance (difficulty falling asleep or staying asleep and excessive sleepiness) due to alterations of the circadian timekeeping system and/or misalignment of the endogenous circadian rhythm and the external environment." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3523094/
Key part of this being "persistent or recurrent". In other words, people who have been struggling with this for a long time and have it reoccur after trying out different strategies.
Adding a distinction could help. Perhaps "voluntary night owl" vs "involuntary night owl".