It would make some sense that there have been unknown Skrull infiltrators on Earth who have been operating since well before the Kree-Skrull War, except that when Rick Jones accessed the Destiny Force, he was able to expose at least Craddock as a Skrull. I don't know if the Destiny Force would have any limits, so that the existence of any other Skrulls on Earth at that time should be made impossible, or whether it can be argued that Craddock's public denunciations put him into Rick Jones consciousness.