Those [dead] are not flagged (it would show [flagged]), it's algorithmic. Usually brand new accounts where another old account will need to click 'vouch'. There sometimes aren't enough users browsing the /new queue. Especially all the github repositories became boring to me, for example code that was pushed to github only 5 minutes earlier with no documentation. 'Show HN' is the most misunderstood label and some users use it for blog posts or websites they didn't work on (like a wikipedia).
I remember your website and see it in my browser history so I most likely clicked 'vouch' (browser history doesn't tell).
It has 8 upvotes and not listed on /show. That's usually a sign that friends upvoted. By that I mean accounts who visit hackernews, upvote and then leave again. I'm not saying that happened here, I've just seen this algorithmic behavior in the past, for example I checked twitter and the author posted an 'upvote my submission on $url'. Apparently that's normal for producthunt but discouraged on hackernews. I have no insight into the actual algorithms.