Tattoos and smoking are behavioral choices, though. US employers can require tattoos be covered with clothing or makeup, same thing for piercings and jewelry. They don't have to give workers "smoke breaks" or provide a smoking shelter for breaks, either. There are alternatives to simply not hiring someone (discriminating) based on personal choices, that still fall within a legal and civil rights framework.

It got trickier with our employer-subsidized Health Insurance system....which gave employers a lot of leeway to "dictate" personal behaviors, even outside the workplace, since an insurance actuarial could say all sorts of employee behaviors added to overall "operating costs" via higher health insurance premiums. That kind of hiring practice can quickly turn into a messy, slippery slope where any employee benefits can be seen as negative.