Every other resolver supports EDNS
Archive.is only works with resolvers that support EDNS
Cloudflare decided not to support EDNS
That itself is a defendable decision but I do feel for a popular site they could implement some sort of fix.
dig @carl.archive.is archive.is A +noedns
curl http://134.119.220.26 -H 'Host: archive.is' -v
I'm not a dig expert, but I believe this means it works without EDNS. I think that means archive.is is specifically blocking Cloudflare's servers, not blocking all non-EDNS requests.