Though this argument is mostly posed through the perspective of accessibility (which I don't intend on engaging with here), this has sparked general discussion on the meaning of the '/hj' tone indicator, mostly via attempts to disambiguate it which, in its multiplicity and inconsistency, ironically reinforced its inherent ambiguity as Mitch retrospectively commented. However, the futility of this endeavour instead reveals that perhaps its ambiguous nature is exactly what makes '/hj' such an appealing and reliable crutch for people to rely on when the words and syntax they choose become further removed from any standardised or subversive formation of meaning via language. As Mitch stated, "Anecdotally speaking, most of the time when I've seen people make short lists of the tone indicators they find the most useful, /hj usually makes it to the top five." This is because '/hj' is evidently very helpful to the communicator.
Mitch stated that "Unfortunately, 'half-joking' doesn't mean anything. 'This statement is partially, but not completely a joke' does not give me any information about what is meant by it, or how I should interpret it." However, it does communicate something; it communicates ambiguity, albeit in a roundabout way. Instead, 'half-joking' provides neither guidance nor direction about the message's vague meaning or interpretation. As Mitch noted, a lot people somehow intuitively understand what is meant by 'half-joking'. To demystify this intuition, I turn to the framework of post-irony.
"A central element of post-irony is the obfuscation, ambiguity, watering-down, degradation, or simple lack of meaning and intent in statements and artwork, and whether the creator or disseminator intends this to be celebrated, decried, or met apathetically can itself be part of this uncertainty." -Wikipedia on Post-irony
Through this lens, a particular slew of words with no apparent tone or intent is given meaning through its clear, and supposedly total, ambiguation. However, this new meaning is formed by its very lack of meaning, thus notably separating itself from the formation of meaning from the likes of more traditional interpretation through the inherent or otherwise ambiguous elements in forms of artistic expression. In such cases, meaning informs the creation of new meaning, whereas the intentional lack of meaning of post-ironic expression informs the creation of its own distinct meaning. Similarly, the intent is the lack of intent. I believe it infinitely more productive to simply ask yourself: What kind of tone could possibly come from that?
According to the Oxford Dictionary, tone has two distinct definitions relating to this topic: Stress and intonation of speech, and related senses and A particular style or spirit of thought or behaviour, and related senses. As tone indicators act as a textual substitute for aspects of face-to-face interaction that are lost in written communication, the '/hj' tone indicator can be taken as serving to clarify that this absence of vocal inflections and nonverbal cues inherent to text that would normally be a hindrance to communication is, in this instance, its intent. In simple terms, by clarifying tone, a tone indicator reduces misinterpretation, which helps achieve effective communication. Then, by clarifying a lack of tone, the '/hj' tone tag is achieving the same effect. However, the instance of a misinterpretation in this case is undefined, as there is, in some sense, no intent from the messenger. That is not to say there is no possibility of misinterpretation. Attempting to disambiguate the meaning or intent of such a message will lead you to an impasse.
Mitch argues that since it is the interpreter's responsibility to identify "which half is the joke", the tone indicator is inherently ambiguous, therefore making "statements harder for [him] to interpret than they otherwise would be, which is the opposite of what tone indicators are for." However, this isn't the fault of the tone indicator, but an inherent complexity of a message with layers of meta-irony. Interpreting the message with a different tone would be a misinterpretation, which only hinders communication. The overall argument of the video is built off of the notion that eliminating ambiguity is the ultimate goal. Nevertheless, that very ambiguity is inherent to post-irony.
In the video, the first two of three distinct common uses for '/hj' are presented through the perspective of either irony or sincerity. Through a metamodernist understanding, these two concepts aren't mutually exclusive. In fact, they have become increasingly intertwined, which reveals the shortcomings of a framework that positions irony and sincerity on opposite sides of a linear spectrum.
As for the third of the three distinct common uses for '/hj' that Mitch entitled "ambiguous on purpose", I want to reiterate a few points. Firstly, I understand some people's intent in using this tone indicator is unambiguous (to them at least), however due to its nature demonstrated by the video, this is effectively a futile attempt which only serves to further ambiguate its meaning. Secondly, as Mitch lists off several possibilities of underlying intent for this usage of the tone tag, he implies that the messenger could, if they wanted, use a more unambiguous tone indicator, with the intentional ambiguity acting only as a device to gauge public opinion on a particular topic. This is essentially the principle behind Schrodinger's asshole, which is, as Mitch stated, purposefully ambiguating an unambiguous message. Ergo, it is actively detrimental as an accessibility tool. Thirdly, he stated that the correct use of '/hj' should be to confuse people because it is confusing, despite him mentioning prior that the majority of people intuitively understand its meaning, which seems contradictory, especially if each use is functionally distinct as he asserted. As people are supposedly communicating with a deliberately ambiguating device without issue, even considering it helpful in conversation, it can be inferred that somehow clarity is arising from ambiguity.
Note: I recognise certain terms such as 'post-irony' are poorly defined. I ask that you take them as I present them.
Afterword
It's comedic whenever someone attempts to explain the '/hj' tone indicator, because they always seem to end off their explanation with the attitude of "idk it just makes sense to me" so I sympathise with the frustration. Please note that this is more of a think-piece than a proper analysis. There is no way to ascertain the intent of the messenger. Most of the evidence here and in the video are entirely anecdotal. I could argue that the people in his anecdotes are misinterpreting their own intent by being tasked with disambiguating their own inherently ambiguous message, but I have no way of knowing one way or another.
More recently, the '/silly' tone indicator has seen a lot of use. I think its popularity only further highlights the convenience and utility of this flavour of ambiguity - here's a random forum discussion on it if you wish to delve more into this topic in its contemporary form.