I am very confused by the turn of events that led the Reptilians to squash the Insectoids like bugs in Enterprise.
The Guardians promised the Reptilians that they would become the dominant race after destroying Earth. That promise is why the Reptilians persisted in trying to destroy Earth, even after humans Earth presented evidence that the Guardians had lied about Earth destroying the Xindi in the future.
On their way to destroy Earth it was the Insectoids who credited the Guardians with their recent victory against the other races, and the Reptillians questioned the Guardians and blamed them for the fighting between the Xindi. As a result of that argument, the Reptilians killed the Insectoids.
This seems very backwards to me. Shouldn't it have been the other way around? If the Guardians are giving the Reptilians ultimate power over their society why would they question the Guardians? The whole thing felt weird, since they were on the way to destroy Earth together as planned. Just after quitting the council together and winning their victory against the other races, all of the sudden they have a ten second conversation and one of them destroys the other.