Infiltration of Reddit is done by co-opting all the individual subreddits. I hear from multiple sources that the same thing happened to /r/conspiracy. I imagine that one was on the top of their list. Check out this thread.

That being said, people often delete their own threads for undisclosed reasons. The majority of he audience got to see it anyway, since it stayed up for a considerable amount of time. So if this was censorship, it wasn't even effective.