OP was careful to frame the term. It's not a later edit, as you quote the framing too.
So the intention there is clearly a rhetorical one, that not being the point, but that advertising has managed to manipulate people against their better judgment. In that sense, yes, they are victims.
Besides, believing that people suffering from an ill that is destroying their lives are free to choose (when reality clearly shows they aren't) is a callous remark.
Eating disorders are very complicated. Eating is such a low level activity that easily supersedes any rationalisations. That's why it's a good example of how bad advertising can be. So again OP is right in calling those people victims.
There's clearly a dilemma. Yes we know that there are messages that, on average, create a bias in people towards particular outcomes. So, collectively, you could say that we can be manipulated.
At the same time, we have to assume that most individuals are capable of breaking this spell if necessary, for instance by making a conscious decision to read up on what unhealthy food does to us.
Otherwise, you would have a justification to take away any and all freedoms from everybody.
Commercial advertising is not the only form or motivation for trying to make people do things. "Manipulation" exists in personal relationships, it exists in religion, it exists in political messaging. We even call it dog whistle politics. And the motivations are not necessarily any more noble than those for running chocolate chip adverts.
We don't have an external all-knowing referee to decide what is good for us, what our priorities should be, and what we only do or believe because we are being manipulated. So if we put too much emphasis on this manipulation and victimisation narrative, we create a huge incentive for someone to assume that role.
There is no dilemma. We agree that people can be manipulated to some degree. We also agree that - if they don't suffer from an illness - that manipulation only goes so far. Finally, we agree that we shouldn't force a lifestyle on anybody.
So now you can manipulate (or nudge) people either towards behavior which is considered as beneficial (regular exercise, healthy food, etc.), or you can manipulate them towards unhealthy habits (e.g., smoking).
It is a good idea to limit the ability of actors to nudge people towards unhealthy habits. That will help everybody except a few people who will earn less money. It is also a good idea to foster nudging good behaviors, even if there is no commercial value behind it.
The dilemma only starts to occur if we try to put all things into either the good or the bad box. Probably most ads are in the large grey area in between these extremes. However, ads fostering smoking addiction or obesity should be called out as bad for all of us. There is no downside of this call-out.
We're inundated with health activism constantly, some of it government funded. The only instance informed choice doesn't come in is where people have no access to/ability to afford healthier food.
So the intention there is clearly a rhetorical one, that not being the point, but that advertising has managed to manipulate people against their better judgment. In that sense, yes, they are victims.
Besides, believing that people suffering from an ill that is destroying their lives are free to choose (when reality clearly shows they aren't) is a callous remark.
Eating disorders are very complicated. Eating is such a low level activity that easily supersedes any rationalisations. That's why it's a good example of how bad advertising can be. So again OP is right in calling those people victims.