I don't see a need to litigate the phrase y'all absent a plausible reason such a word would be used in an RFC or standards process document. Colloquial language is best avoided regardless.
On the broader topic, I recall a very hotly contested issue that consumed much time in Westminster and at cabinet level a few years back where the absence of females serving in a particular role in a document was used to argue that they must never be allowed to serve in that role: ordination of women priests.
Now I recall that at the very same time the CoE was going through that issue, the use of gender neutral language in specs was being dismissed by some people (all men) on the basis it was 'nonsense'.
Language has consequences.
Nor are facts or history the relevant measure, the question should be whether the terms are used to give offense. In the UK, to 'Welch' on a bet means not paying after losing and the name goes back to a pair of bookies called the Welch brothers who did a runner after taking a large number of winning bets in the 1860s. But that is now a term that is avoided because in speech it is easily mistaken for a slur on the Welsh.
There are numerous cases of this type where no ill intent might be intended but might easily be taken. But why introduce unnecessary ambiguity? The whole point of the IETF process is to produce clarity.
Whitelist and Blacklist are best avoided because they carry no semantic. The association white=accept is purely cultural. Acceptlist and Blocklist are preferable because they provide more clarity.
There is also a technical argument to be made against at least 80% of the uses of master/slave: the terms simply do not reflect the technical reality. The term is ambiguous in any case, the online dictionary I just scanned has six separate meanings as a noun plus three adjectives and two verbs. That is not a word to use in a spec.
