Consumers are notoriously accepting of error-riddled products. Just look at most software. Ever since the first software package came out with a "as is" license, we've been stuck with buggy software ranging from operating systems to word processors to games.
Food and drug safety regulations don't say that foods must be abolutely free of impurities, rather that they can't have more than a certain amount of impurity.
In some cases, error free products just can't be made with modern methods. Binding machines will screw up a few now and then. Printers will crinkle pages. Rat hair will get into the peanut butter machines.
But in some cases, products may be more error prone for various corporate policy reasons: short deadlines, savings on quality assurance resources, taking on excessive responsibilities, poor coordination of QA staff.
RPGs are in no way the worst offenders as far as these products go, nor should they be considered so, in part because the consequences of there being an error in the game is minor. Drug interaction checking software, drug manufacturing, brakes on a car - these are all examples of products that had damn well better work because the consequences are VERY high.
Let's keep all of this in perspective. We're just playing games. Sure, they're fun and we derive a lot of pleasure out of them. But we're not doing brain surgery and nobody's life is at stake. I'd like a more error-free product, yes. But I'm not going to go ballistic about it.