Who said that? I think what you mean is, being framework independent, hence being able to do things in vanilla JS. The reason why I love Node or React is coz they force you to write raw JS, making you more flexible and through.
Now, React does some crazy ass diffing to make your view rendering run like a Ferrari, do you think you will be able to implement that in a day or two? Well you could if you had a team of 500 top notch coders and lots of money. But you don't so. So you use frameworks to ease up your task but at the same time tip toe around them if you think you can do things without them.