People are understandably suspicious about this, and we don't expect suspicion to go away just because we say so. But this way we can answer in good conscience.
See http://hnrankings.info/9332418/ ; there's only one big drop there, and it occurred in the morning when people would start posting a lot of other stories that would push it down. And even then, it stayed on the front page for many hours; a flagged or moderated story would drop off much faster.
Not everything is a conspiracy; assume good faith.
On the other hand, I'm curious why someone edited the title of the thread. When I originally posted it, I wrote "Gradberry (YC W15)" in the title, but someone edited that out. Since this wasn't a link to an article, there was no original title to match there. What gives?