React fundamentals. Lifecycle method for data fetching

The official React docs says that you should fetch data from server in componentDidMount lifecycle method.

It could sound a bit weird that in case when your component need some data (which is pretty often) you should always wait for initial rendering, including slow DOM api manipulations for the component and its children. It provides unreasonable delay in sending the request to server.

How could you explain why it is a good decision for React team not to implement a special lyfecycle method like componentFetchInitialData (which is invoked at the beginning) for initial data fetching?

The question from the interview that made me confused