So you are describing a scenario where your existing doctor no longer accepts insurance? I'm not sure why you can't get the insurance your preferred doctor accepts.
Still backwards. It's as much about whether the insurer wants to include that doctor's practice as it is about whether that doctor wants to make the (substantial) investment in tying themselves, contractually and logistically, with a given insurer. In most cases, it's the insurer deliberately choosing to work only with a network of doctors and facilities that is limited in size, in order to allow them to manage expenses so they don't go broke taking on the legally mandated huge new collection of people who will cost them more than they will ever pay.
I don't know if you fall into this category or not (I won;t presume to know), but a lot of people just don't want Obamacare to succeed because they don't like Obama.
But you're not asking yourself WHY they don't like Obama. It's because they don't like what he stands for and preaches, ideologically. Some people don't like the concept of the Nanny State's top-heavy, bureaucratic swamp being in charge of more and more of their lives. They don't want their own health care options, which they've been just fine with for years and years, to suddenly start to look more like the disaster the is the VA medical establishment, or the train wreck that is medicare. And since they don't like the politician who says that pushing things that direction is his actual goal, of course they don't support his aspirations, and thus him.
I just don't get the animosity directed toward Obama
Because in the case being discussed, he KNEW that over half the country was actively disliking the prospects of the new law, and that was before they even fully understood what a mess it was. So he knew that in order to get it rammed through in a 100% partisan process, even with a 100% only-his-party-voting-for-it, he had to consciously, deliberately, and repeatedly lie about the most basic features and provisions of the law... and has had to since consciously, deliberately, and unilaterally (unconstitutionally) change and ignore aspects of the law in the name of political appeasement for those in his own party who've realized how ugly it really is. You wonder why people don't like him? It's because people don't like someone who looks them in the eye for months straight and simply lies to them, repeatedly and deliberately. The question isn't why people dislike that, it's how can anyone say they DO?