I have an issue with these kind of memes that are similar to the "it doesn't hurt to know Lisp or Haskell"....whatever.
It might hurt your goals. There's an opportunity cost involved. So you're either learning a new language or digging into the source code of React at the expense of something else.
It's not a zero-sum game, but closer to zero-sum then what these memes would have you believe.
I would say that reading a comment that could almost be construed as dissuading learning might hurt someone's goals to a more significant degree than typing "it never hurts" very very slightly erroneously.
Now if the author had said, "It never hurts to give up everything else you are doing and look at this codebase for 1 year and shirk all other responsibilities" I'd agree with you, but otherwise you're just being pedantic for the sake of it.
I think anyone who works with React or React native should have a rough idea of what’s going on under the hood.
The above article series seems to do a decent job of this for a framework people use day in and day out.
e.g. replace consumption of something like media (netflix?) for learning more about React internals