&quot;...is the cocky attitude that they never need to bother learning any &quot;old, bad practices.&quot; - so before learning ES6 everyone should learn how to use inline onclick events, alerting to debug etc otherwise they&#x27;re &quot;cocky&quot;?<p>&quot;..technology that was released just 4 years ago&quot; - if you haven&#x27;t been keeping up with the news on IE10 then... yeah<p>&quot;I&#x27;d dismiss them for the attitude that their solution solves all the problems without considering potential drawbacks.&quot; - no one said there weren&#x27;t any drawbacks, just when compared with old bad-practice hacks.<p>&quot;but are very difficult to work with. Not someone I want on my team.&quot; - it sounds like the kind of people who&#x27;re using react would be sad about that.<p>This post is evidently about <i>junior</i> developers, just because something is old&#x2F;established doesn&#x27;t make it right or that it shouldn&#x27;t be questioned, because there&#x27;s usually a better way.