1) Yes, there does seem like something might be happening here. I also can't find your posting (or the others) on hckrnews.com. I wouldn't assume that "censoring" is the most likely answer, though. If it's indeed missing and supposed to be there, a simple "bug" is probably a more likely answer.

2) hckrnews.com doesn't actually try to show all postings, only those that "have made it onto the Hacker News homepage". I wonder if despite getting quite a few upvotes, it either didn't make the Homepage or was on for such a short time that it wasn't registered. It's trajectory is shown here: https://hnrankings.info/33498916/. Note that "Front" is at the very top of the page, implying it didn't actually reach there.

3) Your title is kind of confusing, and most people don't use hckrnews.com, so I wouldn't be surprised if you don't get a much engagement here. If you can't find a sufficient answer here, you might try contacting the hckrnews.com author and asking. He gives his email address at the bottom of the About page.