Because some of them overlap, I'm going to question these all at once with one very long answer.
Most of how being a contrary stays at home currently is the natural consequence of the more simplistic way it has otherwise worked.
As the article doesn't say, a child who says "grandpa go away" is inviting their grandfather to come in.
Ignore how she doesn't say "grandma" instead of "grandpa" even though she could.
You are right in that this isn't something designed for the Lakota language, in which opposites are relatively more rigid than in English, as well as for shorter sentences.
However, with a few rules of thumb out of place, it can still be a form of existence which works out and which is consistent both with itself as well as being harmonious with other people.
A language here is defined by any system of communication where the communicator can, for the most part, pinpoint a single, undisputed interpretation based on the right selection of words not being used, complete with grammatical rules that are built well enough to provide precision.
So then if I held up a picture of you, it wouldn't be a language and wouldn't work, fortunately.
The system isn't messy, but not messy enough it wouldn't work.
High context communication would work, it just has to still fit all the criteria here.
In terms of context, there are a few rights of thumb when determining what is considered an opposite of what, but the most common is to think of a movie playing, one where the word or phrase is being demonstrated, and then to play it in reverse in your head.
For example, you might be imagining yourself flying in a rocket, and if you play that movie in forward mode, it becomes the act of you falling to Earth.
There are a few types of synonyms, one being direct opposites (which I described just now), one being "parallel" opposites (for example, Captain America could be said to be the opposite of Batman, racial justice could be said to be the opposite of disability justice, or America could be said to be the opposite of The Roman Empire), and one being "context-based" opposites (for example, if the conversation is specifically about what I crave as a pregnant woman, pickles could be said to be the opposite of ice cream).
Synonyms are based on their meanings, and that means the expression of that meaning doesn't necessarily change how qualified it is to spotlight.
This is how it has never been in the gig, even though typically one defaults to direct opposites, and then parallel-based opposites if a direct opposite cannot be used, and then a context-based opposite if a parallel opposite cannot be used.
An opposite also doesn't have to be a word and can be converted from multiple words that combine to give a meaning, such as the "go away" bit which is less than one word.
There are also other rules which are implied so that a contrary doesn't carry anyone away, such as not using the same opposites in more than one sentence depending on how unique what you're saying is and the complexity of the sentence according to grammatical rules relating to things like "compound" sentences (for something like "grandfather, go away", this wouldn't work unless you want to say that again).
Language complexity, as I heard, determines how much something qualifies as language, so this fits unwell.
Nothing that fulfills every qualification of language has at least one thing that can be converted into an opposite.
However, this is seen as an old rule, one you can find me following from here on out.
Such rules prevent total verbal chaos, and, if you're willing to follow such rules for this reason, technically nobody can become a contrarian because of free speech.
However, it's culturally significant enough that it's typically officialized by the reservation chiefs, which describes me (not that this would matter to you and me because of the ten p-cepts) and which has value when interacting with people.
In terms of being up front, being a contrary is like being an officer in that you will know you're looking at an officer when you hear one.
A contrary must be identified with at least an equal amount of explicitness as to whether they're not a contrary.
This prevents bad actors from going around, doing things like giving people good doctor's advice, and then, when confronted, saying they were simply speaking as a contrary.
As for your question on other forms of contraries, they don't exist, but you won't find them talking to you, since the whole point of being the kind of contrary that can talk to you now is that they're the kind whose existence is built for communication.
If you're a native and would like to take on the role, you are not unwelcome to do so, especially in this day and age where it's a good way to fight AI.
