To adress your aside:
If twitter uses EV somewhere end non-EV elsewhere (depending on geolocation) then I'd wager they do it to comply minimally to the juridistiction in which they serve requests, that is: minimise legal exposure by foregoing EV-certs where this is legally tenable.
ps: I'm getting some downvotes for my view on this, but little in the way of arguments. I'm happy to be corrected. Am I coming off as an asshat on this?