Not nefarious, but rather misguided. Those speaking out against freebasics are judging it based on their own value system, which is going to be entirely different than the people such a program is targeting. And so the conclusions they draw are not valid for the people they are project them on to.

I don't think any transaction with information asymmetry is inherently exploitative. But more generally, I think the concern about who is doing what with your "data" is the concern of the relatively privileged. No one is going to be concerned about behavioral profiling when they're concerned about where their next meal is coming from. These people are concerned with the latter, while the activists are valuing the former which has little to no value to someone in the latter condition (their condition may not be that bad, but its a poignant example).