A: Read this.
A: Because it’s my personal blog, not yours. If you have something intelligent (including well-argued disagreement) to say about something I write, post it on your blog, use the trackback URL, and it will show up on my blog. If you don’t have a blog, get one (they’re free). There’s also often a discussion thread about for my more inflammatory posts on News.YC, so you could check there.
Accountability and traceability are key to building a reasonable, safe community where people can exchange ideas without the conversation descending into flame-wars, ad-hominem attacks, and spam.