Ask HN: Why is the 40-comment penalty being applied to Show HNs?

First, I'm extremely appreciative of Hacker News, its moderators, and the forum it provides for poor builders like myself to get some eyeballs on our infant products at no cost via Show HN.

However, it seems the 40-comment penalty is being applied to Show HN posts, which seems counter-productive to me. Isn't the whole point of Show HN to generate healthy discussion and answer user questions? Shouldn't they be exempt?

(Yesterday I posted a Show HN that had reached #15 on the front page when the 40th comment came in. Ding! Welcome to page 3. Irony: Several comments were my own, replying to questions.)

Source: http://www.righto.com/2013/11/how-hacker-news-ranking-really-works.html

I surely hope this isn't true.

It's the anti-flamewar detector, which kicks in when a thread has more than 40 comments, and there are more comments than upvotes.

Interesting, I didn't know about that penalty.

Should it factor the overall down-voting of comments as part of the equation?

Just read the part of the linked article relevant to the 40 comment penalty. My question is: assuming that this algorithm works in general, why would it need to be different for Show HN? What makes them different with respect to vote to comment ratios?