FOOD WASTAGE
I hesitated to cite this one. Is this really a moral blind spot now? I suppose a fair number of people are already vaguely aware that a great deal of food is thrown away in certain parts of the world such as the US -- e.g. past-the-date produce, uneaten food from large restaurant portions, etc. But perhaps this is something that, for most people, is still a blind spot. It isn't hard to imagine a hungry future in which people would look back at our time and condemn it.
EARTHQUAKE VULNERABILITY
This is another one I thought about, didn't write, then decided to go ahead and mention. Again, many people are aware of the apparently likelihood of a catastrophic earthquake(s) along the West Coast of the US, etc. If this occurs, then people will denounce the foolishness (moral blindness, even) of having built and lived there. Conversely, if, a century from now, no serious earthquakes have occurred since Big One(s) became a topic, the foolishness of "hysterical" people who predicted terrible things might be denounced. The common element is that people foolishly like to point out the foolishness of previous generations.
Earthquake vulnerability is an interesting one. Of course, obviously prone areas tend to have that fact taken account of in their building codes, and most people living there are aware of the problem. However, there are some areas where this is not the case. The area around New Madrid in the centre of the continent is a good example of this.
I can think of another moral blind spot. There is at least one source of disaster ranging all the way from losing a city to an extinction-level event, for which it can be said that at least getting advance warning would be cheap - at least on the scale usually addressed by governments. I speak of near-Earth asteroids. Currently, the best estimate is that we don't even know about the existence of better than 90% of these. And we aren't even looking for them!