"English Terms in an Executive Order by President Donald Trump

Hi, everyone. English is not my first language, so I have a question. I'm not trying to politicize anything; I just want to get this right.

I was reading an executive order from President Donald Trump called "Securing Our Borders", and I came across these two words: "illegal aliens." So I looked it up on the internet and found an article from The Washington Post (2019) that said the term is used in United States law or something like that.

So I assume the term is not xenophobic/racist, is it? As a non native speaker, to be honest, it sounded kind of weird.

I definitely need to investigate and learn more about the topic, so if you have any suggestions, I'd appreciate it.