It is normal behavior, yes. But it comes at the expense of the cheated on party. The term here is "parental investment" and is roughly how much energy a party has to invest in the offspring.
If the male tit builds the nest and provides food for offspring that is genetically not his it puts it at a disadvantage and it is definitely exploited by the female.
Think about it. In many species there is unequal parental employment. That's just how nature works. Is it really "exploitation" in the human sense of taking advantage of someone else?
Yes. Obviously. And whether or not the exploitation is "programmed" is irrelevant. After all everything is programmed.
I have no idea where I'm going with this, but that phrasing still seems off to me.
Just upthread, "rape" is used in the animal context too. You could similarly apply your argument to that behavior, claiming that the term has moral baggage that's uniquely human, but I think it'd be just as wrong-headed.