This confirms my thoughts that weaver thinks she is the alien franchise
I think that's kind of a fair assessment, but I have a couple other theories.
1. She may have been method acting in a way. Considering Brown mentions that plenty of other actors didn't have the same relationship with her (based on their claims) that he describes in his diaries, she may have been working behind the scenes to affect their on-screen chemistry. Aaron behaves in a manner around Ripley that's kind of uncomfortable and insecure, but based on his character he's also the insecure second in command who merely goes around repeating what Andrews says and trying to look tough, when we know he's just doing that outwardly rather than evoking who he really is at his core. He's clearly terrified of the prisoners and the Alien, and also Ripley. I think it works on screen. Plus, Brown admits that she apologized to him afterwards, so it ended up not being as personal as it felt in the moment, at least in the long term. Of course, if what he says about Fincher is true, that he was constantly on his side in the context of his interactions with Weaver, and his quote about her "vampiring" the scene or whatever, then maybe she was just being mean and egotistical. But I find it kind of hard to believe that's the case.
2. She was credited as a "co-producer" on the film, and actually had the authority to make decisions about what took place on screen. It was the first time she had been in that position, according to IMDb. And she superseded Fincher in authority (and especially
Ralph Brown), as directors are beneath producers, especially 27-year-old music video directors. She could have been exercising her right to vocalize what she did and didn't want based on her position within the production staff as a co-producer, which she was entitled to do.