Here are a couple of lines of Pali (the first two lines of the verse at the end of the sutta):
“Yo dhammayāgaṃ ayajī amaccharī,
Tathāgato sabbabhūtānukampī ;
Here are the same lines from the translation quoted in the question:
He who, unstinting,
made the mass-donation of Dhamma,
Here are the same lines from another translation:
The Tathāgata has made the Dhamma-offering,
Unselfish, compassionate towards all beings;
Looking at the Pali, I think it's saying:
- dhammayāgaṃ -- gift of dhamma
- ayajī -- something to do with offering or sacrifice?
- amaccharī -- without being a miser
- Tathāgato -- the Tathagata
That just leaves sabbabhūtānukampī to translate.
I think that sabba means "all" or something like that ... that must be where the "mass" translation is coming from
And bhūtā means something like "a being".
And kampī, I'm not sure, maybe perhaps being "still" or "not trembling" ... or maybe the second translation above suggests that this bit somehow means "compassionate"
Anyway, the Pali suggests to me that the "all" there is associated with the "beings" (i.e. "to all beings") -- and that agrees with the second English translation that I quoted.
So I thik that what's translated as "mass-donation" in the first translation means "donation to all" ... i.e. that the Tathagata gave the dhamma to all beings.
But maybe the sutta (both the Pali and the second translation) is really saying, more literally ...
- making the dhamma-offering unselfishly
- the Tathagata (and something: compassionate, maybe) to all beings
... i.e. maybe the offering-of-dhamma wasn't "to all" ... and instead only the kampī (i.e. the stillness or compassion or whatever that means) was "to all beings" ... maybe the text could be read either way. This latter way might be more compatible with other suttas: e.g. he was teaching "those with little dust in their eyes" and so on, rather than everyone.
I don't understand though why the word "mass" also appears in previous lines of the translation you're using (because "sabb..." doesn't appear there, in the Pali: it's only in the verse).
Maybe this is the clearer or more straightforward, more literal translation:
- The Dhamma-offering
This was said by the Lord…
“Bhikkhus, I am a brahmin, ever accessible to entreaties, open-handed, one bearing his last body, an unsurpassed physician and surgeon. You are my own legitimate sons, born from my mouth, born of Dhamma, fashioned by Dhamma, heirs of Dhamma, not heirs of material things.
“Bhikkhus, there are these two kinds of giving: the giving of material things and the giving of the Dhamma. Of these two kinds of giving, this is the foremost, namely, the giving of the Dhamma. There are these two kinds of sharing … these two kinds of help … these two kinds of offerings: the offering of material things and the offering of the Dhamma. Of these two kinds of offering, this is the foremost, namely, the offering of the Dhamma.”
The Tathāgata has made the Dhamma-offering,
Unselfish, compassionate towards all beings;
Living beings revere such a one,
Gone beyond being, as chief of devas and humans.