Ernest, that's fine for you, but again, you're parsing words to argue for a point no one anywhere has ever explicitly laid out. In short, according to your arguments, we should NEVER use quote marks in dialogue, since the words are NEVER QUOTED BY ANYONE. Just as that's an incorrect assumption, so is your assertion that the dropped quote guidelines isn't valid because no one distinguishing between "quote" and "dialogue".
There are many punctuation marks that are used for multiple things, and what they mean varies with the context and application. When you look at the dictionary meanings of a quotation and dialogue they're two different activities, despite often (but not always) using the same punctuation marks. Some examples of the same punctuation mark having a different meaning due to the applications are:
. Is a full stop at the end of a sentence. Or it can be a decimal point in a number 7.95. And it's also called a dot when referred to in a URL or an email address, among other things. The same mark but different usages.
, A comma has similar multiple uses in sentences, or in numbers like 1,200.
' and " While both the apostrophe and double apostrophe can have multiple uses in different ways in different styles to mark a nickname, Thom 'Dusty' Rhodes, or a book title such as Ernest Bywater's 'The Falcon' as well as being one way to quote from a text or a speech, or used to designate the section of a fiction story the author is setting as a character's dialogue. The use of the single or double apostrophe can be used in any of those options, based on the style you're using. While a single apostrophe can also be used to designate a missing letter or letters in a contraction, or a possessive form of a noun.
- Can be a dash, or a minus sign, or a few in a row to indicate a break in the flow of the text, such as a scene break.
In a similar way there are multiple ways to designate quoted material, one of which is to use the apostrophe or the double apostrophe, another is to use the block quote method. Which you use is the author's choice in fiction, in some non-fiction works the style manual preferred by the publisher will often designate which to use for what quotation - some manuals say to use block quotes for all long quotes and some don't.
Now down to answering the question you emphasize - The punctuation mark used for fictional dialogue is an apostrophe or a a double apostrophe, note it's a punctuation mark, it just looks the same for multiple uses. It's like the full stop and the decimal dot, they just look the same, but have a different meaning and a different name with the different usage.
It seems to me the core of the usage is the name some people use for the punctuation mark is causing them to see what it's used for as the same as the name and it being the only name for it.
I'll admit having Asperger's Syndrome and being pedantic in many things often means I see things in black and white, and that's the situation here. I see a quote as being very different to fictional dialogue, as per the dictionaries. I also see the same punctuation mark is allowed to be used for both activities in various situation, but I don't see the activities as being mutually interchangeable with the rules for one flowing over into the other in all situations.
For simplified uniformity and clarity of what I write I always use apostrophes and double apostrophes in pairs, except for where I use a single apostrophe for contractions or possessive nouns. Where it's appropriate to do so my preferred method of showing a document within a story is to use the block quotation method.
typo edit - amazing how you miss the typos in the little reply box, but they jump off the page when posted