I don't think it's OK for anybody -- corporation or otherwise -- to saturate me with messages that are tailored to my psychological characteristics that are only partially under my own control.
I should know. Worked for a small agency. First did print ads. Then specialized in PPC. Find the thing that keeps your target market up at night. That's what gets them to click. When I ran campaigns for "wellness" companies (which were scammy to begin with), the "stay healthy" angle never worked. The ads that performed the best were the ones that made the user feel anxious: Feeling tired? Weak? Gaining weight? Looking older? That sort of thing.
Think about that for a second. Is that nice? To intentionally make someone feel bad about themselves, to sell them something? Of course not.
Is it legal? Yeah. Should it be? Probably. But just because you can, doesn't mean you should. Unfortunately, that's not the win-at-all-cost mentality of business.