Any alien civilization capable of posing a physical threat to us probably will not recognize a significant distinction between us and say maggots. Better start worrying about coordinating our response with the maggot response...
It's more likely that they don't distinguish if they visit, because they're not here to study or make contact, but to extract resources or remove the solar system out of the way. Not too dissimilar to how clearing the amazon forest. There's no need to ask the native animals living in the forest for permission to clear it.
Completely in agreement with the second paragraph.