As explained in this comment under the question, that question was linked by a very popular science-communication-humor website, which drove a big spike in traffic and votes about three years after the question was asked. Consider this plot of score over time:
Once a question has become the top-voted post on a site, new or casual users who are interested in what the site is about might go to the list of all questions, click "sort by score," start reading the first few highest-voted questions, think "hmmm, they're right, this is pretty good," and add an upvote. This positive feedback means that the most-upvoted questions tend to run away from their neighbors.
The common internet-name for this phenomenon is related to the exponential growth of a virus in a naïve population. But since we're a physics community, we might call it thermal runaway instead.