I used the term "truther" as an attempt to be honest -- admitting that I pretty much agree with them, rather than trying to pretend to be a devil's advocate or fence-sitter.

I don't see how that's a failure of filtering.

The rest of your first paragraph is basically ad-hominem, as far as serious discussion of this issue goes. If I'm upset, I try not to let it dominate the conversation -- this is a rationalist community, after all, and I am a card-carrying rationalist -- but I also believe it to be justified, for reasons I explained earlier.

"That's normal" -- so are you in the "people aren't rational so you might as well give up" camp along with komponisto? What's your point?

If you want to calibrate, you could look at Holocaust and HIV denial. I'm told they are well described by the above quote. or any medical controversy.

Holocaust denial and HIV denial are easily refuted by the available evidence -- along with global warming denial, evolution denial, moon landing denial, and most religions. 9/11 anomalies manifestly are not, given that I've been trying for years to elicit rational rebuttals and have come up with precious little. Please feel free to send me more.

Often it is best to silence incompetent skeptical inquiry.

Do you really believe this? Why? Who determines that it is incompetent?