Care to explain how it is apparent?
I do understand it, and no company should be responsible for stupid customers. We don't agree, apparently. See what I did there?
Apparently you don't because you think the lawsuit was over her stupid action. The lawsuit went through because McDonald's had been covering up burn accidents for over a decade. She just wanted her medical bills covered ($20k), McDonald's told her to shove it but was found out that McDonalds knew of their temperature being too high for over a decade and had been found grossly negligent in their actions as over 700 previous burn victims had been paid off or scared into dropping any legal action against McDonalds.
In the end the lawsuit was not about her and was found to be a legitimate lawsuit not because she was stupid but because McDonalds breeched it's legal duty of care.
The McDonald's case is a widely studied tort case study. The judge didn't throw out the case because it was a fact case and therefore a trial by jury. The Jury didn't find the case to be frivolous because the coffee was hot enough to cause first degree burns requiring skin grafts and 2 years of medical treatment. McDonalds had been covering these cases up for over a decade and because of that they were found grossly negligent by a jury.
When taken in the context that 'oh some old lady burned herself with hot coffee and sued' it seems highly frivolous. However, the lawsuit went further than that after the facts came to light. McDonalds has changed its cups, used more protection, and put an easier to read warning on their cups as a result of the lawsuit. Others continue to try and sue McDonalds over hot coffee "accidents" however, none have been successful since this case.
So you are correct in that no company should be responsible for stupid customers; however, every customer has a right to hold a company responsible for stupid (reckless and irresponsible} actions.