Star Trek fans have become very sensitive to introductions of new characters, aliens or historic events arguing that things that haven’t previously been mentioned ‘break canon’ or disrespect lore.
This piece by Inverse shows how profoundly TNG retconned Federation, Starfleet, and main characters’ history on the fly.
Worth thinking about.
Calling it retconning is a strech when it mostly added new story where there was none.
That’s a point.
Although in the case of the introduction of the Cardassians, there were significant contradictions vs the geopolitical situation of the Federation as presented repeatedly in the earlier seasons of TNG.
In relation to fan outrage though, even modest ‘filling in gaps’ — or ‘dancing between the raindrops’ as the EPs of SNW call it, is frequently met with with complaint that “no one has ever mentioned that before.”
I was alive during the '90s, I’m Italian, in Europe we had the Yugoslavian Wars, my country was involved in the Kosovo war… If you asked anyone on the street they would have told you we were living in the most peaceful time in recent history.
The Federation is huge, it’s plausible that an important conflict like the one with the Cardassians still ranked low compared to those with the Klingons or Romulans.