A Simple Misunderstanding
It was literally a miscommunication. We didn't even know that they'd arrived, let alone that they had come on a humanitarian mission to help us. How could we possibly understand that?
For a hundred years we'd been broadcasting stillborn beings into the cosmos. For a hundred years we'd been trying to say hello, while they had been trying to understand what was killing us. Trying to understand why these lifeless husks kept arriving on their doorstep? They understood that we were trying to initiate contact. What they couldn't understand was that our messages weren't us. That we were back on a planet trapped inside the arrogance of our carbon based bodies.