I've been reading a bit about the history of Quakers' plain speech and their rejection of the singular pronoun 'you'.
(worth recalling their history with regards conscientious objection)
"George Fox however was not the first of the religious writers, who had noticed the improper use of the pronoun you. Erasmus employed a treatise in showing the propriety of thou when addressed to a single person, and in ridiculing the use of you on the same occasion. Martin Luther also took great pains to expunge the word you from the station which it occupied, and to put thou in its place. In his Ludus, he ridicules the use of the former by the, following invented sentence, “Magister, Vosestis iratus?” This is as absurd, as if he had said in English “gentlemen art thou angry”?
But though George Fox was not the first to recommend the substitution of thou for you, he was the first to reduce this amended use of it to practice. This he did in his own person, wherever he went, and in all the works which he published. All his followers did the same. And, from his time to the present, the pronoun thou has come down so prominent in the speech of the society, that a Quaker is generally known by it at the present day.
The reader would hardly believe, if historical facts did not prove it, how much noise the introduction or rather the amended use of this little particle, as reduced to practice by George Fox, made in the world, and how much ill usage it occasioned the early Quakers. Many magistrates, before whom they were carried in the early times of their institution occasioned their sufferings to be greater merely on this account. They were often abused and beaten by others, and sometimes put in danger of their lives. It was a common question put to a Quaker in those days, who addressed a great man in this new and simple manner, “why you ill bred clown do you thou me?” The rich and mighty of those times thought themselves degraded by this mode of address, as reducing them from a plural magnitude to a singular, or individual, or simple station in life. “The use of thou, says George Fox, was a sore cut to proud flesh, and those who sought self-honor.
George Fox, finding that both he and his followers were thus subject to much persecution on this account, thought it right the world should know, that, in using this little particle which had given so much offence, the Quakers were only doing what every grammarian ought to do, if he followed his own rules. Accordingly a Quaker-work was produced, which was written to show that in all languages thou was the proper and usual form of speech to a single person, and you to more than one"
www.worldspirituality.org/quaker-language.html