Mensa is pretty well known for being a club for people with a superiority complex, so that probably wasn't a one-off incident.
I read somewhere that people with really high IQs need just as much support as people with really low IQs because the world is generally built for the middle, and I feel that. It's the functional question - as you say in your example, you might be able to do this genius thing but not take care of yourself. How many great artists of all kinds were like that throughout history? Composing great works but drinking themselves to death or committing suicide or needing others to care for them.
And IQ as a measure of intelligence is super flawed anyway - it's pretty well rigged to show people who have had certain upbringings as "smart" and everyone else as "not." It's not as much a measure of raw intelligence and problem solving as everyone thinks it is. And even if it worked as touted, it doesn't account for holistic intelligence like, the farmer who can't do algebra but he knows really well what the weather patterns mean and the texture of the soil and what that thing happening with his crops is about and what the animals are doing and so on. It doesn't account for emotional intelligence, either.
Basically, everyone has strengths and weaknesses, imo, and it's folly to try and say one is better than the other.
Given what we know know about multiple intelligences and different learning styles, it is definitely folly to use IQ as a measurement of anything much more than the capacity to solve mostly abstract puzzles. But you typically can't bake a loaf of bread with that, or fix your bicycle tire.
I typically like to use a metric along the lines of "are you thinking and growing?" to determine where someone is in their life path and direction... if you are not open to learning and growing, then it can become a bit of problem, and I sense a lot of the world's ills being a result of what I might describe as "willful ignorance;" the process of people actually taking pride in their lack of wisdom. Which is — IMHO — part of what I think of as "thought shaming."