It's how you'd talk about a dog that you know the sex of, but if you didn't know you'd probably use "it". An LLM doesn't have a sex or gender, so I think the natural way to refer to them is "it".
"Es kackt auf's Auto" feels slightly weird to me, if I didn't know whodunnit, I'd probably say something like "irgendwer hat mir aufs Auto gekackt" ("someone pooped on the car"), although there is a also "irgendwas hat mir aufs Auto gekackt" ("something pooped on the car"). My guess is the majority of German would choose the first sentence and anthropomorphize, but maybe I'm projecting.
It's an interesting question, after all. Thanks for bringing it up, haven't talked about pooping on cars for a while ;)