Okay kiddo, you know how some foods taste sweet and some taste sour, right? Well, a long time ago in China, some really important guys were trying to figure out the best way to live a good life. They tasted three things that they thought were the most important parts of that: vinegar, which is sour; sugar, which is sweet; and wine, which is bitter.
Each of these things represents something in life, too. The vinegar represents the difficulties and challenges we all face. The sugar represents the things that are good and make us happy. And the wine represents the sadness and tough times we all have to deal with sometimes.
So the guys who tasted these things were called "the vinegar tasters" because they were trying to figure out how to balance all of these things - the sour, the sweet, and the bitter - in order to live the best life possible.
It's kind of like when you want to eat a really good meal, right? You need to balance out the different flavors - maybe have something sweet like dessert, something savory like meat, and something sour like a salad dressing. The vinegar tasters were doing the same thing, but with life instead of food.
So that's why people talk about the vinegar tasters - they're a symbol of how we can all try to figure out how to balance the different parts of life, even when things get tough or sad.