Don't argue with Americans, they are always right
Americans typically state accusations as facts. When they accuse you of something, you are already guilty in their eyes, and if enforcement lies with them, you will be punished. You are guilty because accused, and there is nothing you can do about it; no defense is possible. The administrative state, which is a corporate (and university) affair as much as a public governmental one (the institutions and their bureaucracies are similar) works this way.
When Americans make their accusations, which are to them not hypotheses but conclusions, not claims but articulations of certain knowledge, they believe that they are right on the facts. It is often easy to see that those are not only potentially in dispute, but more importantly, not so clear. But you, the accused person, cannot possibly say anything referencing the uncertainty, because you will be encountering someone who is absolutely convinced. You would be showing weakness if you allowed that they could be right but it does not seem so to you. The other party will not care about that, and say, yes, I know I'm right. They don't know that, but they say it, and may think they do. It as if uncertainty is impossible for anyone who has any experience of anything happening. If these people were more fair-minded, and judged generously rather than ungenerously, then they would know that what they perceive or remember may not be the exact facts of the matter. Then they might ask, or say this is what they remember or their impression of what happened, and in any case they would admit to the uncertainty. But people almost never do that. The reason is that our culture, politically and morally, is a combative one, with everyone competing against everyone else. Also, they are acting exactly like a legal prosecutor (or defense attorney) would: in court, people of a partisan orientation represent what they want in terms of claims of fact that they must present with certainty. Then someone else, whose job it is to find out the truth of the matter, a judge or jury, does that. But few people think like judges reasonably considering matters; that is extremely are, and three things militate against it:
1) The dominant model in America of thinking in cases of interpersonal conflict is that of the law court, not, as is more true in France, the philosophy seminar.
2) The media follow the same model.
3) The corporate and governmental bureaucracies that make up the administrative state combine prosecutorial and juridical approaches to addressing problems, with no defense involved or possible. Simply, those in authority make decisions.
4) The dominant tradition in American philosophy, "analytical" philosophy, thinks this way. A plausibly true statement in a text or essay of analytical philosophy normally does not articulate, nor allow for, uncertainties, vagueness, the merely apparent or possible, etc. This is true even more in terms of style than content: the style is normally self-certain, authoritative, declarative. That arguments are then made to justify positions is perhaps a detail easily forgotten, since the media mode of discourse only uses argumentative discourse as rhetoric, as advertising and marketing also do. The analytical style makes arguments after the fact and their status is as rhetoric. It will seems as if the position taken is what matters (and the person taking it losing or winning, as in formal debate) more than the thinking involved in considering it.
5) Capitalism works this way. And not just marketing and advertising, which are this way by consequence. The company and its bosses pursue their own interest. They are well motivated to identify their interest with something like objective fact.
What I find is that this makes dealing with most Americans a tiring annoyance. It is also further evidence of how most people today process information and make decisions in pursuit of their goals, but do not really think. A thinking person is often uncertain of what he should really believe. Our culture is not hospitable to that. But then again, it's not a thinking culture but a practical one.