Sorry you aren't on the list, but by all means, go ahead and add yourself (there's a link on the right sidebar). And as to why you aren't on there, here's a quote from my announcement post:
"As an homage to the original Ecosystem, I took the list of weblogs from Instapundit and VodkaPundit's blogrolls --- which was how the original was created. This time around I also added in Bill Quick's list, as he's got a darned comprehensive one himself. This naturally gives the TTLB Ecosystem a very political-blog slant in general, and warblogger slant in particular. Depending on how popular the new version becomes, we may see it branch out into the wider Blogosphere, or perhaps it will remain focused on the political zone. Either is fine by me..."