Not sure it's quite a "rule", but: You took a discussion about a story, and derailed it with a completely different story. That gets annoying. Also, the way you did it is a trope that I personally find highly annoying ("if you care about X, then you must/should/need to also care about Y"). I consider it highly manipulative... except that for some reason, your post fit the pattern, but didn't set off my "I'm being manipulated" alarms. You didn't seem to be trying to do that, but you still hijacked the discussion.
Note well: Your story is worth talking about. It just doesn't belong in the discussion of this article.
As to why the other article disappeared... HN has a "flame war" detector. Any article that has more comments than upvotes has probably become a flame war. They usually or always kill those. You can vouch for them, though, as a way of saying that this shouldn't have been killed. (You need to have "show dead" turned on in your profile to still be able to see it. Also, you may have to have some level of karma to be able to vouch for something.)
In addition to what others have mentioned, there's an explicit rule to not accuse other commenter of organized efforts to promote or suppress something without clear evidence, especially not on quite emotionally charged reasons.
Note well: Your story is worth talking about. It just doesn't belong in the discussion of this article.
As to why the other article disappeared... HN has a "flame war" detector. Any article that has more comments than upvotes has probably become a flame war. They usually or always kill those. You can vouch for them, though, as a way of saying that this shouldn't have been killed. (You need to have "show dead" turned on in your profile to still be able to see it. Also, you may have to have some level of karma to be able to vouch for something.)