What do you mean, we never got to see Bronn and Tyrion interact? Bronn fights for Tyrion in the Trial by Combat in the Vale

Really interesting theory.

It's fake. No further explanation needed.

Nobody's paying me to watch it, and I'm not a writing student learning what not to do, but I watch it. And I'm just curious as to why you're posting on an episode you haven't seen in a season you haven't watched.

Their goal can't be just to kill all the humans —as you say, they could have done that on the first day. The aliens are vulnerable in some way, and need humans to overcome or compensate for that vulnerability. Hence the people in suspended animation in the pods.

Fanatical faith in a cult explains it.

Could be. They seem a bit petite though, don't they, for humans? Or are the beings in the space suits just AI representations of them? But then why do they need to be in a chilly environment and always keep the helmets on? Can't tolerate earth's environment, in which case defeating them might be as simple as…

Don't you think the reason they need humans is a deliberate, central mystery of the show, rather than some kind of oversight or thing they forgot to explain? I think it will be revealed at some point, but not yet.