self using intoxicants

i was reading the scripture

This answer mentioned:

I personally use ... Dharmafarer for in-depth analysis

There's an analysis there of many though not all suttas, including SN 12.61.

I'll quote here what it says about the bit you cited in the OP, but it's also worth reading it all -- it's not long, there are footnotes, and I find the careful formatting makes it easier to read, without missing details, but also seeing the structure:

The three graspings

The Assutava Sutta says that the uninstructed worldling may be able to regard the body with disgust as its change and decay are clearly apparent, but not so in the case of the mind. He clings to the mind, thinking, “This is mine (etam mama); this I am (eso’ham asmi); this is my self (eso me attā).”

The Saṁyutta Commentary calls them the three graspings (gāha) and explains them in terms of craving, conceit and views. The self is held to (ajjhosita) by being swallowed up by craving; it is owned (mamāyita) by being owned by craving; and it is grasped (parāmaṭṭha) by being grasped through views.

“This is mine” (etam mama) is the grasp of craving (taṇhā,gāha);
“This I am” (eso’ham asmi) is the grasp of conceit (māna,gāha); and
“This is my self” (eso me attā) is the grasp of views (diṭṭhi,gāha).

“The grasp of craving” here includes the 108 thoughts of craving, (etc.)

I don't know how well you know all these terms and their contexts? What the Dhamma says about them?

In summary I think it's related to doctrines about anatta and "identity-view".

this is difficult to apprehend

Is it?

There are nearly two hundred topics tagged anatta on this site, maybe it is hard to pin down, or something.

i am not capable of willing myself to stop using intoxicants, so how does this dhamma make sense?

I'm not sure how that ("I am not capable of willing etc.") relates to the quote -- except that that topic is presumably a preoccupation, like a lens through which you see things. Like when I lost a loved one, that was my immediate experience of dukkha and the lens or context through which I read and applied the dhamma.

Re. the phrase in the title, i.e. "self using intoxicants", I think that the anatta doctrine explains that what a person might consider "self" is in fact a conditioned set of aggregates -- which may arise from conditions/causes/components, and ceases when those cease.

In fact I think the same is true of a habit of using intoxicants -- the habit is conditioned, temporary, and ceases sooner or later (often but not always before the end of someone's life), e.g. in a different environment or when something else changes or arises or ceases.

And I suspect that this kind of habit is related to -- causes and is caused by -- self-views: "I have a habit", "I cannot will", "I like the intoxicant", "I don't like something else", "they can't tell me what to do", and so on.

You (and the sutta) may be right, when you say that it doesn't seem like something "I" can do.

Doing way with "identity view" is, according to Theravada, a significant first step towards enlightenment, not trivial:

• A "Stream-enterer" (Sotāpanna) is free from Identity view ...
• How are 'conceit' and 'identity-view' not the same?

I suspect that major addiction may be overcome, not just from some "internal" change like "will power", but when something in the "external" environment changes -- new knowledge or responsibility or incentive, new (and better) friends, losing a former antagonist, changing location so as to make the intoxicant unavailable, maybe something like that.

With respect to ruben2020's answer, which seems to suggest being mindful about the arising, I think another method may be "learning from experience" and "seeing the disadvantage" of an action. For example if the result of an action is feeling that "I am in hell", then isn't that an action to avoid repeating?

It may also be to do with developing "wholesome" or "skillful" desires. You may discover from experience that "using intoxicants" makes it more difficult to do what you want to do -- both, while intoxicated and afterward -- and therefore change your preference, towards avoiding intoxicants.

what exactly grows dispassionate towards the body anyway?

Grammatical English requires a subject for every verb: e.g. there's no such thing as "running" (action) without there being a "runner" (agent).

I think that Buddhism accepts that as a "convention" -- footnote 43 on page 59 of The Debate of King Milinda The Debate of King Milinda:

There are two levels of truth; conventional truth and ultimate truth. In the conventional sense it would be wrong to say that a person does not exist; but in the ultimate sense it is right. In reality there is only a continuously changing stream of mind and matter, which we mistake for a person.

I think I find it more useful to think in terms of "dispassion exists" or "passion is ceasing, the passion that was has ceased" -- instead of as "I (I, I!) am dispassionate". Part of the point of it is to become less ego-centric in view, less conceit, less grasping.

And the very question, "Ah, dispassion ... but who is feeling it, eh?" is an example of manufacturing, reinforcing, creating, perpetuating a self-view where maybe it's not needed nor beneficial.