Dude, she's been given shit jobs her whole life, it's likely this is her first time seeing aliens in person. She's having a reaction like "Holy shit, look at that jellyfish thing! Oh, it can talk by blinking? My bad."
And the Keepers aren't sapient at all: they're all biological machines, tasked with their programming. How is she to know that those can't talk, but the Hanar can?
Because the fact that it is the first time WE see the aliens doesn't mean that it is the first time a character already living in the Mass Universe is seeing those aliens. Are you telling me that, because she had "shitty jobs", she never saw a photo, or a video of somethin in the Citadel?
We're talking broad strokes here. Giant, grey, four-legged thing. Boom. They're both identical. I also said "from a distance." An elephant's most distinctive feature is its head. Same with the Elcor. If you saw them from any other angle though? Hell, I could probably grab a screenshot of an Elcor's ass and compare it to an elephant's and not be able to notice any difference at all.
The phrase is "I can't tell the difference" not "broad strokes". If you are going to flat out ignore what Ashley says and replace with what you think she should have said, the discussion is pointless.
Go ahead and grab an screenshot from an Elcor ass and compare it with an Elephant, and you will see that they are different.
Other sci-fi doing it shapes how the people writing the game approached it. If whoever wrote that line figured that calling aliens animals wasn't that big a deal because sci-fi had been doing it for at least 50 years, it can change the entire context of why and how the line was written, approved, and voice acted. Notably, Ashley's VA - who IS black - was very surprised when Ashley's "space racist" meme spread around the internet.
I don't see any reason here to say "it is okay for the character to be rude because other characters in other universes have been rude before".
As for who the line was written, approved and voice acted:
Also, why are you using my example as a reason to call Ashley stupid? How would you know if a Hanar was intelligent at first glance? It's a giant jellyfish that talks by blinking. If you're not close enough to hear it talk or see it use tech, you'd never know. Same with the Elcor, really. https://masseffect.fandom.com/wiki/Elcor?file=Codex\_ME\_-\_Elcor.png That could just as easily be somebody dressing up a pet. This circus elephant image doesn't look all that different to the Elcor's (aside from the pants).
Ashley going "I can't tell the difference between aliens and animals" in the seat of power of the galaxy, is akin to a white person going to the Bronx and say something insulting about black people. It can't be excused by saying "well, I have never seen a black people before, so it could have been just as easily someone's pet".
Even if she is really ignorant, it is still in bad taste and in a terrible location to do that comment. So, stupidity.
Remember, this is the same universe where nobody knows what the Quarians looks like despite having the Space Internet for thousands of years and the Quarians only going into those suits 300 years ago. Clearly, information does not travel the same. It's possible Ash could have been taught it in school (and I'm sure the Marines would have taught her how to kill or heal other alien races as needed if nothing else), but it's also possible she missed those days, or they deemed other things too important (Imagine if your high school course load also had the histories of a dozen alien species you had to learn).
There is a reporter in the three games that have a camera, then you have another that travels in the Normandy. Obviously inverviews are being filmed. We are not talking about something that happened 300 years ago, we are talking about something that happens right now.
Not to mention that there are not a dozen different races in the Citadel.
