The plural of anecdote is not data, it's perception.
Human knowledge of the natural world is generally acquired either by observation, or hearing about something from someone. The nature of this latter method comes in varied forms and has its pros and cons, owing to the fact that testimony of others is generally less reliable than the senses. Let's put a recounting of some historical event as an example, you can read about it in a book, or you can ask someone who lived through the event what it was like. Differing testimonies in various media will lead to variations in the story, and it's sometimes hard to know what is real as Ryunosuke Akutagawa has shown.
Either way, your consumption of this second-hand information will affect how you perceive the event, and while you can hear more perspectives to assuage your opinion, it's impossible not to build your own opinion on such matters. The way the testimony is shown can also affect your perception, as you cannot impart information without a rhetoric.
In fact, let's get a bit recent, let's use the whole virus mess to show how stories of deaths and sickness are used to drive public opinion. One year into this thing, the general picture of mortalities is that of this sickness mostly killing elderly people with comorbidities, but earlier on in the frenzy, stories of children dying of the virus are plastered all over the news. Statistically this is a rare event, but the purpose of such stories is not to hype up an impossibility, it's to widen the age bracket of those who could die from the virus, no matter how weighted the chances are. A child died of the virus, so you're effectively deathly worried that your kid might also perish from it.
A selfsame summary of vaccine effects is taking place, with vaccine promoters hunting for people who declined vaccinations dying horrible deaths while those opposing them will cite someone who has gladly accepted the vaccination and then contracting either a terrible side-effect or death. Pervasive in all these anecdotes is the possibility of dying or mortal harm. Showing that not following measures results in death is a good sell not for the efficacy of the measures but for the moralizing effects of it; I have been spared of this harm because I am not irresponsible like them.
Anecdote has also been used to argue both for and against measures, for and against interventions, and whoever gets a hold of the narrative also get a hold of the anecdote. Ultimately, the goal of every anecdote is for the receiver to become personalized by it. Statistics rarely convince people, but personal stories do as stories—unlike numbers—are easier to relate to.
In the end, the use of anecdote is not to prove that something in the event foretold happened, but that since it has been purported to have happened, it can possibly happen again unless something is to be done.
