
Probably just ignorance. I also didn't realize that word was a slur until I went to high school.
Media also has shows like "Gypsy Bride," it was said in the Hunchback of Notre Dame which is a children's movie, etc. so whoever translated this probably just wasn't aware and went for the closest term that matched.

The word has been used as a slur for a specific group of people who were considered wanderers. Being outsiders, they were not always welcome in certain communities and were targets for people to blame when misfortunes came.
The specific instance I'm remembering is, I think, from the Hunchback of Notre Dame where it's implied in some of the songs that the Romani people have sticky fingers ie they steal, aren't honest folks, and have cult beliefs.
Racism against them was bad enough that Hitler also threw them in the concentration camps during WWII.
Was liking this so far but then they dropped the G-slur for Romani people on chapter 11. Checked Tapas version and it says, "my mother says she has wanderer blood" while Bato and Mangago.me says "my mother said she had G-slur blood."