To be fair to Pressly, via his diary we find out he did a complete 180 degree turn from his previous beliefs.
More than what she thinks or doesn't think of aliens, I was more than a bit disturbed at the totally cavalier manner with which she dispatched Wrex on my first playthrough. I felt a bit creeped out when she started pumping rounds into him with that detached expression on her face and the total lack of remorse following that.
I felt like Ashley never gave Wrex another thought - I guess that didn't really sit well with me.
And Ashley, either via dialogue in ME1 or via codex entry - I know I read it somewhere - does some amount of turn from her previous beliefs. Not a lot, but then, she's not racist. And it's a more personalized matter of development, similar to Pressly's. It isn't about entire species when either of them change, either - it's about the individuals involved that they've dealt with.
Regarding the Wrex situation, Ashley really doesn't deal with him in any different a way than Shepard with a renegade action does. Wrex is dead in my primary playthrough, who is a Shepard that lets nothing get in the way of the mission - certainly not racist. Also, whether Ashley shows remorse on her face or not has no relation to whether she enjoys personal satisfaction from killing the evil alien scum. If she had a big freaky smile on her face, then hey, I'd be right there with you.
Really? Because I remember her telling my Shepard, within earshot of Garrus and Wrex, that she doesn't trust them. That doesn't seem very respectful to me.
Fair enough on the Pressly and Cerberus points - hence why they are not quoted. Though, I would argue that minor characters are worth analyzation when related to the conversation, but the point has been made.
Regarding her "I can't tell the aliens from the animals" line - way to take it out of context. You're trying to use this as proof of racism? Okay. How, exactly? Because quite a few of the alien species look animalistic in appearance. Furthermore, given that it's voice-acted, we can look at tone - and it's said in the same tone with which Kimberly Brooks delivers all of Ashley's joking/sarcastic lines. People have been crying about this line and taking it out of context for years, but it hasn't been a winning point yet. Don't be like those idiots.
Ashley sums up her own outlook quite well during one of her dialogues on the Normandy, regardless. In it she states that all she's talking about is she expects it to be realistic that every species put itself first - Asari will value Asari above others, Salarians will value Salarians above others, Turians will value Turians above others, etc. Why? Because it's human nature.
And to finally get to your quoted mention about her distrusting Garrus and Wrex - yes, initially. It's also a qualified distrust, which you left out. Her distrust in the specific instance is about letting them in the nuts and bolts of a prototype Alliance vessel, which is really no different than if someone in the U.S. military didn't want someone from Britain flying a brand-spanking-new military plane.
