The headline is clickbaity, but the advice is solid. Use progressive enhancement and don’t worry about polyfilling.
When I say ‘Stop supporting IE’ it means to me that I won’t go the extra mile to get unsupported features working in Internet Explorer, but still make sure Internet Explorer users get the basics, and can use the site.
The problem I’ve regularly encountered in my work is that I don’t get to do my job the way I think is best for both me and my employer or client. The employer, who isn’t the web development expert, almost always has a clear idea of what real web development is supposed to look like: Single-Page-Apps and React (or React-like frameworks).
An intimation that it wouldn’t be the right solution for this particular problem is taken as an admission of incompetence.
I’ve experienced this. And I think this observation is even more true when it comes to recruitment.