As Aurélie said, it is a bit old fashioned, but you could say that it is there in order to put some kind of emphasis on it: as in NOT AT ALL
1) It is to make sure that we have no detractors at all
2) I didn't think at all at what you said
in the first sentence, you go straight to "de"... because the object of the sentence is just a noun. In the second sentence you have to go for "à ce que", because the object is a verb.