I strongly disagree with your "even if" hypothetical.

Dialectics are a process for arriving at truth, not the source of truth itself. I think this is something hard-core rationalists often seem to forget.

In terms of time, emotional energy, and so on, evaluating arguments is very expensive.

Ignoring an argument because its source is "odious"ly biased is the political equivalent of using heuristics to prune a huge search space. It may not always give you an optimal answer. But then, climbing every ant hill to the bitter end may not get you to an answer in your lifetime anyways.

And remember, in an argumentative setting, the search space is adversarially constructed. So you can actually be pretty damn certain that without heuristics, you'll never find the truth.

> this is not reason enough to assume the worst

The degree to which people are "assuming the worst" seems to be one of the major sources of disagreement.

FWIW I don't think many of Damore's detractors are "assuming the worst" from the outset. Complaints about the essay tend to identify specific claims, specific phrases, specific arguments that serve as heuristics for choosing not to continue evaluating the argument in good faith.

You can argue against those heuristics all you want, but I don't think that this argument is even possible to have without some heuristics. Case in point: Damore uses his own set of totally unsound heuristics (see e.g., the complaining about "political correctness", the graphs that are actually just pictorial representations of prior assumptions, and so on).