You are mixing 3 separate issues into 1.
1. If someone knows all the information, but still chooses to make the wrong decision.
2. Someone is being told wrong or incomplete information, leading them to make the wrong decision
3. Someone is being forced by external means into making an wrong decision.
Two and three are already illegal, under fraud and coersion.
Im solely talking about 1. Because if you don't believe people have full agency in that regard, you have to prove to what extent can you determine what is deception. You can't just willy nilly say that something feels immoral, and therefore should be banned.
It is possible to believe that people have full agency and allow them to make wrong decisions, but in the case of wrong decisions about harmful addictive things where such people tend to later themselves wish they had not gone down that path also believe that we should not allow others to help them make that wrong decision.
Well I agree that 2 and 3 are settled matters, but 1 is simply hiding an unexamined definition of what choice is.
So, what does it mean to choose something with full agency?
You appear to be making the assertion that any economic exchange taken by two adults with full information is morally acceptable. Is that correct?
If so, would you accept the following as moral actions?
Financial adviser charging substantially above-market fees to recent widows, who lack experience in finance (All information is available, but not understood)
Selling heroin outside of a drug rehab clinic (All information available & understood, but under compromising circumstances)