No, and that's what I was asking. Have we reached the point where we can ignore IE?

IE8/9/10 for most purposes, yep. IE11, no (IE11 is used more than Edge as far as I've seen)

Which means the answer is no, we can't ignore IE yet and that means I won't be touching this library with a 10 foot pole.

Can they afford to turn away users?

Maybe not today, but in a few months or a year, possibly. IE is dying and Edge is taking its place. Supporting IE just makes maintanance more difficult, doesn't it?

Not if you want to design a site for any of the millions of government organizations out there who still require support for IE9+

If only there was some sort of standard library for government organizations to use [0].

[0] https://standards.usa.gov/

As long as they double their budgets that's fine.