The actions of an individual are the individual's responsibility, not the fault of society. If a murderer said that media violence caused him/her to kill someone, even if they were deranged, you would hold him/her criminally responsible for the murder he/she committed. You wouldn't blame the media that millions of people watch without becoming killers. You'd only be justified in saying, "it was an influence in this individual's case", and nothing further. The same principle applies in making attributions to any sort of media, including models in magazines.
Unless they are photo-shopped into oblivion, which admittedly does happen occasionally, these models depicted are real human beings. It is simply not true to say that these humans that exist are unrealistic. You can expect a degree of stylised photography due to the skill of the professional photographers, but this can't make it "unrealistic".
I expect if you saw a model in real life, you wouldn't think looking at them might make people anorexic. You'd probably think, "wow, she's pretty, I'm going to go to the gym so I can look like her!" Or conversely "Wow, she's pretty, I'm going to the gym so I can sleep with her!" Depending on whether or not you're batting for the girls' team.
You are correct in stating that people "shouldn't model themselves off them" if they do it so badly that they "end up dying in the process". That would be an example of hilariously poor execution on the part of the prospect, as opposed to the fault of the modelling industry.
I see you drinking milk on a magazine, so I decide to drown myself in milk; the safe consumption of milk is entirely my responsibility. You are not to blame. It would be unreasonable to hold you accountable for anything I do after seeing you drink milk. If I seriously cannot deal with a picture of you drinking milk existing, I must call upon professionals to help me deal with everyday sights.
Pragmatically, if one person every so often decides to look at a model on a cover and stops eating, it is more parsimonious to deal with that single person's issues. Restructuring society around the potential for innocuous things to exacerbate mental illness, is the most inefficient, difficult, and unreliable solution humanly possible. Or should you be held responsible for my milk-related antics and be prosecuted for manslaughter?
If people are so delicate that seeing Kate Moss compels them to starvation, the problem is definitely not the shape of Kate Moss. I'll go so far to concede that people with serious mental difficulties might be destabilised through the constant media exposure, but this is a problem that starts and ends with mental illness.