By Isaac Butler
(Note: This might not actually be a new argumentative fallacy and if someone knows the real name for it, let me know)
Blogging has, as far as I can tell, abetted, and possibly created a new argumentative fallacy. It basically goes like this:
Instead of addressing the argument actually made, you attack the argument for not talking about things it isn't talking about.
I'd like to call it Ad Distractio or something.
This started a long time ago on liberal blogs like Atrios. The seed of it was commenters complaining about Atrios not addressing their pet issue. It hit the theatrosphere a few years ago and seems to have subsided, but I've started seeing it in more and more places.
The easy way to generally spot it is a blog response to something contains the phrase "why isn't he/she talking about...." It will then proceed to not engage the argument at hand and instead list all these things that the article could have mentioned and didn't, often things that get more and more irrelevant as you go.
The problem with this is, of course... that people tend to write about things that interest them (or things they're paid to write about, or hopefully both) and people have the expertise that they have. You cannot know literally everything about everything, someone is going to know some things that you don't. So it's an easy way for people (particularly academics who have hyper-specialized knowledge) to pretend to be counterarguing something when they aren't.
What lies at the heart of this fallacy is that many people read to have their own worldview reified, and if something doesn't do that-- particularly when the subject matter is one that they are familiar with -- they'd rather dismiss it than grapple with it.
If someone is genuinely not considering something relevant, of course that's worth pointing out, but it's rarely grounds for dismissal and it's almost never a real argument on its own.