Does that seem like a strange question coming from an editor? It shouldn’t–nor should one leap to conclusions regarding the answer.

I submit that the answer is a qualified yes. It has to be qualified due to these observable realities:

• Not all communication is formal and professional. If we’re texting or PMing on FacePalm, do we really need to stress over mistakes? Not sure about your phone, but on mine it’s enough of a pain in the ass just texting understandably. There are many contexts in which I care about upper case, avoiding loose spaces, and so on. This one tends not to be such a context.
• Language does evolve, however powerfully language conservatives rage against ‘deterioration.’ That there has been deterioration I think few can deny, but at any given point in time language differs from previous points of time, and its future will differ in turn. Look at the styles of 1800s and 1700s writing and you can see how it happened. There is never a time at which the orthodoxy is static, meaning that “perfectly correct” is a moving target.
• As if that weren’t enough, many other countries have their own versions of English. There are more English speakers in India than in the United States. Australian and New Zealand English have marked differences, and I don’t recommend going there to try telling them they’re doing it wrong. Same for South Africa. Irish English and British English also differ from ours, with the added fillip that “The King’s English” is supposedly the mother tongue. Canadian English is akin to US English but with noteworthy British influence. If we’re going to talk about “correct English,” whose correct English do we mean? That of the largest numeric grouping, which would be Indian English?
• Writers can be very effective yet be doing it “wrong.” When I get a ms that is written in some bizarre-looking form of English, I ask myself whether it’s effective. Some time back I did a line edit on a vanity book about of an elderly Alabama gentleman’s country music career. It sounded like what it was: a book written by a rural Alabamian nonagenarian. To edit it into some semblance of English perfection would have meant destroying the author’s basic tone. As it was, parts were a little repetitive and sometimes unclear, but his tone was familiar and regionally correct. His audience would understand every word of it, even find it warm and comforting; what was more, who would want to excise the author from his own autobiography? It’d have been lunacy.
• At the opposite pole, I read a book by an L.A. gangster who converted to some variation of Islam and reformed. as i recall, it did not use upper case. It sounded like it was written by a moderately educated gangster. It was raw, real, personal, and effective. If he’d come to me as an editor, I doubt I would have tried to regularize his language. The way he wrote made it feel like the reader was getting to look at an otherwise inaccessible world. That I couldn’t think of a compelling benefit that would make it worth losing that feeling testified to the effectiveness of his style.

Qualifiers noted, I have indeed seen the quality of US English education and composition decline over my lifetime (don’t blame me). That gives it something in common with the rest of education during my adult life. With a dead battery, most people now are without their arithmetic. I was watching a frightful display of ignorance on Big Brother where someone thought London was in Paris, or Paris was in London. Most every day I read at least one adult female person refer to herself as “a women.” People not only don’t learn physics and geometry; they don’t even learn to adult. (There’s a verbing you might expect me to hate and reject. Nah; that word arose in reply to a genuine need, right around the time it became de-stigmatized to live with your parents once you grew up.)

All the more reason, some might say, to give no willing ground in the erosion of language standards. I understand the outlook on an emotional level. From a practical standpoint it feels like a King Canute activity. I’d rather fight for the differences that make differences, such as the abuse of “literally” to mean “figuratively.” We need that word. Without it we have no way to clarify whether a statement is hyperbolic or, well, literal.

In the end, my editorial outlook is that everything comes down to judgment and context. Does it work? If it does, any change requires a compelling case. If however its language causes it to fail, we need to rethink and adapt. There is no editorial Scripture, just some textbooks and style guides; they should be consulted but not worshipped or thumped at anyone. In the end we must apply our best understanding.

If it were as easy as just pointing to the arcana of the Chicago Manual and interpreting its holy words, this job would require far less experience and discernment. (I might start terming that crowd the “Chicago judiciary.”)