It's not a moral duty, it's a Robb Report level luxury. One does not need to be particularly articulate or present a rational argument, especially when dealing with matters of morality. Sadly, rhetoric and appeals to emotion, empathy, and common sense are more effective if your goal is to sway others.

> This phrase does not mean "All good men should continually natter on". It is also your moral duty to present a cogent argument

What I was trying to say is there will be times where you are not as prepared as you like. It's not about presenting an airtight, cogent argument, it's about having the courage to say something like, "Officer, stop beating the shit out of this guy in a wheelchair. He's clearly isn't resisting and you're being a dick."