Unfortunately, I have witnessed this firsthand where the desire to "own" the other side grows faster than that of getting to the best (possible) answer.
Winning at all costs is indeed a dangerous game to play.
They don't know these things aren't true. Modern disinfo and psyops is sophisticated enough to be credible and plausible to its targets. It aims to identify already-existing grievances, perspectives, worldviews and frames of reference, then select actual events out of the random soup and create false narratives for them that reinforce or justify those pre-existing beliefs. Like how we see shapes in the clouds or the stars and ascribe meaning to them where none exists. It manipulates the human mind's penchant for pattern matching, even where the pattern is just a statistically inevitable artifact of randomness.