Not to nitpick, but the word "rationalize" usually has a negative connotation — to rationalize something is to attempt to justify/explain something that wasn't

Not to nitpick, but the word "rationalize" usually has a negative connotation — to rationalize something is to attempt to justify/explain something that wasn't a rational choice to begin with [1]. In short, you're implying that people's decision to use ES6 wasn't based on a conscious, analytical decision. If that's not what you meant, perhaps "justify" would be a better word to use. Or maybe just: "Why?" [1] https://www.merriam-webster.com/dictionary/rationalize https://www.merriam-webster.com/dictionary/rationalize