Identity: Part 1 - Completely Nonsensical (Spoilers)
The Kaylons' reasons for invading Earth are to spread out to other planets since they're running out of room on their home planet and to eliminate biological beings. What sense does their current action make?
They don't breathe oxygen and there are an infinite number of uninhabited planets they could start civilizations on. It would only makes sense to do that and then start an invasion once they have a sufficient number of established worlds. Why would they start a war agains a federation of hundreds of planets, before they have the numbers to pull it off?
Worse they went with a miniscule invading force. These are supposed to be intelligent beings.
On a side note, it's been said again and again that they don't feel emotions. So how is it they claimed Isaac was humiliated?