Intent to understand is but one of many possible points of failure. The world is infinitely complex, but our minds have this nice feature where they hide the vast majority of that complexity from us. The problem is though, the simplification process is vastly different for each person, not to mention they are not working from the same set of data.

So when an internet discussion takes place, particularly on special topics like politics, the odds of each person considering the topic from the same perspective (with the same desired outcomes, etc) is very low. Add on top of that the fact that most people seem to lack realtime awareness of the simplification process running in their heads, leaving each participant in the discussion with the false impression that they are talking about the(!) facts(!), when the reality is very different.

Situations like this is where some variation of the recommended approach in TFA could perhaps come in handy, but people seem to be not terribly fond of speaking precisely and accurately, especially when it comes to politics.