It's such a plausible conclusion that it makes sense to draw, even if it turns out to be mistaken. Absent the ability to read minds and absent an explicit statement, we have to go on what is likely.

The best we can say is that it is a sufficiently predictable conclusion. Had the author not underestimated inferential distance he could easily have pre-empted your accusation with an additional word or two.

Nevertheless, it is still a naive (and incorrect) conclusion to draw based on the available evidence. Familiarity with human psychology (in general), internet forum arguing (in general), XiXiDu in particular or even a complete read of the opening thread would suggest that the advice you dismiss is clearly, obviously and overwhelmingly good advice for XiXIDu. You have also completely misread the style of dominance manoeuvre Anatoly was employing. Petty sniping of the kind you suggest wouldn't naturally fit with the more straightforward aggressively condescending style of the comment. ie. Even when interpreting Anatoly's motives in the worst possible light your interpretation is still sloppy.

Absent the ability to read minds and absent an explicit statement, we have to go on what is likely.

'We' need to go on the expected consequences of our choices. Your choice was to accuse someone of questionable motives and use that as a premise to give advice for how to handle a serious mental health issue. You should expect that your behaviour will be negatively received by those who:

• Don't want XiXiDu to be distracted by bad advice (that is, to be encouraged to continue exposing himself to a clearly toxic addiction) as a side effect of Jiro playing one-upmanship games. Or,
• Don't like accusation of questionable motives based on mind-reading when there is reasonable doubt. Or,
• Think you are wrong (in a way that socially defects against another).