Equivocation about the actuality of the next world is a wrong view. DN 1:
- Herein, bhikkhus, a certain recluse or a brahmin is dull and stupid. Due to his dullness and stupidity, when he is questioned about this or that point, he resorts to evasive statements and to endless equivocation: 'If you ask me whether there is a world beyond — if I thought there is another world, I would declare that there is. But I do not take it thus, nor do I take it in that way, nor do I take it in some other way. I do not say that it is not, nor do I say that is neither this nor that.'
Similarly, when asked any of the following questions, he resorts to the same evasive statements and to endless equivocation: Is there no world beyond? Is it that there both is and is not a world beyond? Is it that there neither is nor is not a world beyond?
It's impossible to simultaneously hold a wrong view and right view.
The sutta you quoted clearly says that equivocating in the way the eel-wriggler does is wrong -- it does not, however, tell us why it is wrong. It does not say "it is wrong because there is a another world and he needs to accept that".
The above equivocation is also repeated in the next sutta, where the viewpoint is attributed to Sanjaya. What becomes clearer on reading it there, is that it makes the holder of the view unable to do anything effectively because he cannot make up his mind. He is not even sure that action has an effect:
DN 2 wrote: If you ask me: 'Is there another world?' if I thought so, I would say so. But I don't think so. I don't say it is so, and I don't say otherwise. I don't say it is not, and I don't not say it is not. If you ask: 'Isn't there another world?... Both?... Neither?'... 'Is there fruit and result of good and bad deeds?... Isn't there?... Both?... Neither?... Does the Tathagata exist after death?...
The Buddha can be seen to equivocate (can be interpreted as equivocating) on many of the same issues. The difference is that the Buddha actually knows something about these things and can therefore act on them. He knows which ones are worth discussing and which ones are not, and of those above, the one he does discuss is whether there are fruit and results of good and bad deeds and that he redefines in his own way.
And this, I believe, brings us back to the point about modern "materialists". They aren't eel-wrigglers. They don't spend any time at all wriggling between "maybe there is, maybe there isn't". And more to the point, they understand that actions have results. They are reasonably certain there is no other world but as I have said before, every single one I have ever met would give up that certainty in the face of good evidence, so on two counts they are not the kind of materialists described in the suttas: their materialist views don't lead them to actions inconsistent with the dhamma, and in the case of every Buddhist atheist I have met, their relative certainty that this is is their only life makes them want to practice *more diligently* not less; and they have no doubts that actions bear fruits.