Good article, broadly speaking. I quite agree that one of the larger problems we have in discourse is not just that people lack open minds, but that they lack any semblance of knowledge of rhetoric (your Rule 2) and how to apply data and statistics.
One of the most common breaches of rhetoric is how some (most) reject information based on source. For example, I used to argue a point based on a study that was published by Jacobin. Readers were shocked — shocked, I tell you! — to find me referencing Jacobin. Well, Jacobin has some thoughtful articles, and the role of the left is often to add some perspective to the cold capitalism of the right. I rarely agree with their writers, but this particular one was insightful and forward looking.
Anyway, I digress. I do have some quibbles with your article: :-)
Tell a capitalist that children were exploited and essentially enslaved in early capitalism and they often retort that it was better for people because they were able to support their families or (with shocking backward logic) that it was somehow because real, “pure” capitalism has never really been tried and it was really the fault of whatever minor regulation was in place at the time.
Hmmmm. As a capitalist, I would never make that argument.
I would instead make the point that social standards evolve at different rates than economic necessity. It was not considered odd for children to be put to work in factories in early capitalism, because their families were accustomed to them being put to work on farms.
the “but Obama…”, “but Hillary…”, or now, “but Biden…” retorts are never in order when some damning fact about president* Trump is pointed out.
The “but somebody” arguments are not, I agree, relevant to the extent that they are not exculpatory for the specific policy/person being criticized.
However, they are highly relevant in that the “criticizer” is usually wishing to argue not only that the person/policy is BAD, but it’s UNIQUELY BAD. In this case, the “whataboutism” is relevant.
For example (and I have argued this one often), a common attack on the current President’s tax scheme is the lowering of the corporate tax rate, which is an anathema to the followers of Mr. Sanders. Now, you may believe that lowering the corporate tax rate is bad policy, but it is not UNIQUELY bad policy, as shown by the fact that Mr. Obama (and by association, Mr. Biden) wanted to lower it also. THUS, an opponent wishing to criticize Mr. Trump for this policy must also criticize Mr. Obama for the same, or be exposed as a close-minded partisan rather than an open minded economic commentator.
This therefore ties in to your “Rule 3”.