Leslie Cohn-Wein's main point:
While [lots of divs, inline styles, focus management problems] are valid concerns, it should be noted that nothing in React prevents us from building accessible web apps.
True. I'm quite capable (and sadly, guilty) of building inaccessible interfaces with React or without.
active class and build a tabbed interface quite quickly. But did I build the HTML in such a way that it's accessible by default? Did I deal with keyboard events? Did I deal with all the relevant
aria-* attributes? I'll answer for myself here: no. I've gotten better about it over time, but sadly my muscle memory for the correct pattern isn't always there.
I also tend to listen when folks I trust who specialize in accessibility say that the proliferation of SPAs, of which React is a major player, conspicuously coincides with a proliferation of accessibility issues.
I'm optimistic though. For example, React has a blessed tabs solution that is accessible out of the box. I reach for those, and thus my muscle memory for building tabs now results in a more accessible product. And when I need to do routing/linking with React, I reach (get it?!) for Reach Router, and I get accessibility "baked in," as they say. That's a powerful thing to get "for free," again, as they say.