“Leftists typically try to understand conservatives in a way that is not true, for the purpose of disagreeing with them.”
That’s part of it, but that’s not all of it.
Another aspect is that leftists are regularly dishonest about their own political beliefs. They think the ends justify the means, so they believe if their goals are lofty, then they can adopt deception as a justifiable tactic, and market their politics deceptively. Then they assume that conservatives are also being deceptive, so they balk at taking our stated goals, principles and arguments at face value for that reason as well.
Yes, and one of the tools they use to be dishonest is language. Like the way they call abortion “choice”, or what they classify under racism. All of their methods can probably be found in Rules for Radicals, that book dedicated to Lucifer, which Hillary and Barack were pupils of. Lucifer being the first radical, and a deceiver like them. They know they can’t win honest debates, so they play the game you described—deception, with a lot of false accusation.