I just googled it! Wow, we were the bad guys! The aliens did act a bit odd I thought e.g. they appeared to only ever attack in self defence!
A: The humans fired the first shot. It was a warning shot, yes, but aliens didn't necessarily know that.
B: They didn't attack anything that was a direct threat to them. One could argue that the attack on the freeway by the shredders was pointless, but it's explained later on that that freeway led to the mountain where they were setting up camp.
C: They allowed the humans to rescue the survivors from the other destroyers. I mean, they had a perfect chance to eliminate any threat right there, but instead sat by and watched the humans go on their merry way.
D: This doesn't really have anything to back it up, but I got the feeling the force field was more for their own protection than to isolate the heroes.
E: When the humans captured one of their scouts, they went on a rescue mission to retrieve him/her/it. Leaving someone else behind to sabatoge the ship's engines was only a secondary objective.
F: The other scout (maybe it was the same one that had been captured earlier?) Let the guy with the suitcase go, and grabbed the handle to stop him shaking.
G: No real evidence for this one either, but none against either: The humans are quick to assume that the aliens are calling for a full invasion, but more likely given the circumstances, they were just trying to get picked up from this crazy planet where the natives are shooting at them for no good reason.
