"Psychological violence is the use of verbal and non-verbal communication with the intent to harm somebody mentally or emotionally or to exert control over somebody." (WHO)

For example, neglect is nowadays typically included in a definition of psychological and emotional violence, also on legal levels (domestic violence, childcare).

I consider it to be psychological violence, causing harm on a mental level.

I bet a study comparing sites with dark patterns to sites using the HCI studies for what they were meant for will show that dark patterns cause stress on various measurable levels, which is simply harmful to an organism.

If done on purpose, is is a deliberate form of causing harm to others. Death by a thousand papercuts. Just because we are so used to treating each other violently every day, we can still call it by its name and identify it as ultimately damaging. I would not be surprised if it was a contributing factor to cancers, for example. Yes, miniscule, but still.

By calling it out as violence, I am not saying that there are no worse forms of violence.