DNS servers can't answer more than one question per query because NXDOMAIN is signalled in the message header and so when QDCOUNT is greater than one the response becomes ambiguous.
> 1. Some hosts might want you to use a CNAME record to send them your web traffic, and CNAME records are undesirable for apex domain names because they can't coexist with other records you might need (like MX).…
Those are non-standard proprietary extensions that aren't universally available. Omitting them is not questionable.
They didn't want to wait for multiple queries to finish. If you're interested in a detailed rationale you can take a look through the mailing list archives (though it'll be frustrating reading).
This came up again during http2. The browser vendors just aren't willing to take on the extra latency at the start of the request.
DNS servers can't answer more than one question per query because NXDOMAIN is signalled in the message header and so when QDCOUNT is greater than one the response becomes ambiguous.
> 1. Some hosts might want you to use a CNAME record to send them your web traffic, and CNAME records are undesirable for apex domain names because they can't coexist with other records you might need (like MX).…
Those are non-standard proprietary extensions that aren't universally available. Omitting them is not questionable.
They didn't want to wait for multiple queries to finish. If you're interested in a detailed rationale you can take a look through the mailing list archives (though it'll be frustrating reading).
This came up again during http2. The browser vendors just aren't willing to take on the extra latency at the start of the request.