Atin_Fordo,
Yautja,
15 years ago
Hmmm. My assumption? Time was the determining factor. See, in the first movie, the drone had a reason to act like that: No active Queen was around to do anything, so it made sense to simply eliminate the threats around and not worry about anything else.
In the second movie? Well, you covered that already.
In the third, however, we're back to a similar status as the first. Yes, there is a Queen that is being CREATED, but isn't ACTIVE. There's no reason to capture anybody. They'll just sit and rot for a long time.
Also, consider this. How easily can a chestburster defend itself?
The Queen has yet to get the chance to grow. Meaning that any living beings are a threat to the Queen, and hence, a threat to the Hive. Much easier to just eliminate all threats, and worry about the rest in the long run.
I haven't watched the alien movies in a very, very long time, and I do not pretend to know ANYTHING about Aliens, so I can't say. But those are just a couple of my thoughts.