It's not perfectly acceptable to "know something is wrong" when one does not understand the parameters of the problem at hand. Stating that you "know something" doesn't mean you know something.

I hear many people "know something" about health insurance premiums rising too much, blaming ACA for what they "know" are unnecessary increases in premiums to line the pockets of the fat cat insurance company executives.

Except they don't "know" that the ACA provided a mechanism for far more people to get healthcare for far more health issues. And since you don't get more of something for free, obviously the costs have to be paid somehow. And if they looked at the numbers, they would see that healthcare cost increases have slowed dramatically since ACA was effected.