And also, does it really matter if it was on purpose or not, the end effect is that same, purposefully designing addictive patterns meant to make people spend more time on it, regardless of the mental health of the person.

I can kill a person with a car either intentionally or unintentionally. Of course one is worse than the other, but both are ultimately bad and you should face justice for either of them, even if the punishment might be different because of the motivation/background. But neither should leave you as "innocent".