Earlier quoted context omitted.
Rails is FANTASTIC! I work on a hybrid React-on-Rails application and working on the React portions is so. fucking. painful. Seriously the shit people come up with with this "tool" makes corporate-hack Java programmers look good. I am always taking the backend Rails-y tickets if I have the chance
Blaming complexity on React is a bit like blaming complexity on ERB. The problem isn't React, the problem is the massive hole where React doesn't have an opinion. React improves the area around the hole so much that the technologies we use to fill the void look obviously deficient in comparison.
This is not to say that JS is shit but both JS and Rails have their place. If you want flexibility, you need JS. If you want iteration speed and dev productivity you need Rails.