Speaking as a European, the whole American health system is difficult to understand. Frankly, it's mind blowing.
Unless you're ultra rich (which is an entire echelon above what the normal person might consider to be rich) there's no legitimate reason not to want a universal health care system.
I was reading an article a few months ago featuring an interview with an American nurse working in some sort of specialist care unit for rare brain tumours. She said it wasn't uncommon for people to be admitted with hundreds of thousands of dollars in their bank account, then leave with nothing. Leaving them begging for financial help or having to sell off their home to cover the expense of their ongoing treatment. Many of the patients having mistakenly believed their insurance company would cover the cost.
Despite that, they're arguably still the lucky ones. Most would agree it's better to be broke than dead.
I lost my house as a kid because of an insurance company, I know how dumb it is first hand, and really I think anyone against M4A is just astroturfing or lying, honestly.