Astronomers always think of astronomical events as to when they are seen from earth, not corrected for light-travel times. Even novae and supernovae are designated by the year of discovery, such as Nova Aquilae 1932, or Supernova 1987A. This is even the case when the discovery is made years after the signal gets to earth, as in the case of a nova discovered in 1950 from a study of a patrol photographic plate exposed a half-century earlier; indeed, most novae used to be discovered this way, spotted decades after fading into obscurity by some graduate student huddling over a blink comparator. It is understood that the "real" event may have taken place thousands of years earlier (millions of years earlier, for extragalactic SNs).
The interesting fact here is that supernovae, unlike novae, are very rare events, usually one per galaxy per century, and even in our galaxy few are visible because of dust in the galactic plane. If I'm not mistaken, the last Milky Way SN was seen several centuries ago, before the telescope was invented!. The 1987 event was in one of the Magellanic Clouds.
As for the ignorance of the public, there's not much we can do about that. Grade school kids teach themselves basic astronomy all the time, I did. The material is widespread and available, and with the internet, there at our figertips. If adults have little interest in the subject, no one can be blamed but themselves.
As the great Yogi Berra once observed: "If the people don't want to go to the ball park, there's nothing you can do to stop them."