It doesn't matter (for example) if I am/am not comfortable with ES2015 syntax. A junior developer already made that decision for me when he decided to implement the modal window by adding React, Babel, and Webpack to the project, instead of just writing a two-line event listener and a CSS class. Meanwhile, my colleagues are standing at the kegerator toasting his choice, because how could we ever have maintained or optimized such archaic vanilla JavaScript before without arrow functions and DOM diffing!?
React is not bad. In fact, it is great. But instead of being "an option" it is becoming "the default." Sadness results from being forced by industry trends into using it everywhere, despite knowing that it doesn't solve any problems that I did have while introducing new problems that I didn't have.