We can assume that many HN readers are closely related to Web programming. Either they do it themselves or their wage gets paid because their employers' business depends on Web apps.
If the article is right that it is close to impossible to hire a Web developer that understands all Web security issues and knows to mitigate them, it does not come as a surprise that there is fierce criticism to the article. It basically says you are doing a hopeless job and your employers' business model is flawed.
I'm not a Web developer, but I find the article very convincing. From what I follow headlines Web programming changes very quickly and the frameworks change all the time. Meaning that smart people are not happy with what is available, writing new stuff. Yet I don't think security has been the primary driver for any new framework. They are still parsing text. So let's see whether the author has any fundamentally different approach in his next post (if anybody remembers to read it)
Disclaimer: I work in embedded and our company advertises to be very secure. I know that our security sucks.