Insurance companies say they are not discriminating against people with mental illnesses. Rather, they are struggling to provide the most affordable coverage for the largest number of people.
This paragraph bugs me. Here, let me offer a nice overblown 'equivalent':
Local 'Kill All Gays' advocate Harvey Bunko says he's not discriminating against homosexuals, but trying to provide the best possible benefits for surviving citizens of the United States.
The only honest way to phrase the above (about Insurance companies, not the fictitious Harvey Bunko) would be to say that they are discriminating against people with mental illnesses as part of their attempt to provide the most affordable coverage for the largest number of people -- in other words, they are discriminating against those with mental illnesses because they are usually more expensive to treat.