from what i have read and can remember, this is the only sutta that states the view "there is no self" is annihilationism. In all other suttas (from memory) and from a quick glance at the brahmajala sutta, annihlationists always proclaim "I have no self" or "there is a self but it gets destroyed at death"
I think then that perhaps we have a slight corruption of the text on our hands. If i am correct then it should read as
Having taken a seat to one side, Vacchagotta the wanderer said to the Master, 'Now then, Venerable Gotama, is there a self?' When this was said, the Master was silent.
'Then I have no self?' For a second time the Master was silent.
Then Vacchagotta the wanderer got up from his seat and left.
Then, not long after Vacchagotta the wanderer had left, the Venerable Ananda said to the Master, 'Why, sir, did the Master not answer when asked a question asked by Vacchagotta the wanderer?'
'Ananda, if I, being asked by Vacchagotta the wanderer if there is a self, were to answer that there is a self, that would be conforming with those priests & contemplatives who are exponents of eternalism (i.e., the view that there is an eternal soul). And if I... were to answer that he has no self, that would be conforming with those priests & contemplatives who are exponents of annihilationism [craig- the taking of the view "I have no self"] (i.e., that death is the annihilation of experience). If I... were to answer that there is a self, would that be in keeping with the arising of knowledge that all phenomena are not-self?
'And if I... were to answer that there is no self, the bewildered Vacchagotta would become even more bewildered: "Does the self which I used to have, now not exist?"'
So my take is he was asking
Do i have a self
Do i have no self
reason - Said yes to self this would be ignorant understanding, said that he had no self it would be the same since the question was framed in the sense of "I have no self" and was coming from an "I"
Then the Buddha states "all dhammas are not self" and then if he were to give the answer (in line with supermundane understanding) "there is no self" this would have confused Vacchagotta into thinking "Does the self which I used to have, now not exist?" because he was approaching the Buddha and framing his whole questions in terms of "I"
Its kinda the same tact the Buddha took with "cosmos is eternal or not eternal?. He remainded silent here since they were questions that were coming from the preconceived notion of "I"
It seems to me that if a person says "no self" is annihilationism then this is wrong understanding on the persons part since for something to be annihilated it must be seen to exist in the first place
So if you say no self is annihilationism that means you think there is a self now since something can only be annihilated if its seen to exist
So i cant see how "no self" is annihilationism unless you already think there is a self
Whereas "I have a self" or "there is self" is obviously ignorance and "I have no self" or "there is self but it gets annihilated" is the same
For one who understands Dhamma "no self" cant be annilation view since they understand that "self" only arises in the first place because of clinging and not as a set existing entity