I mean ... practically anything is grounds for taking offense in America. Americans are like people who were suddenly told they're allowed to be offended, and now they're on a binge of being offended by everything. I probably wouldn't yell "hey kid" to my waiter at the Waffle House (or maybe I would, if I felt like I liked the kid). But "chico" is a term of endearment. I've never heard it said without some sweetness and tenderness... it doesn't sound the same as "hey kid" delivered in a derogatory way.