When co-worker behaviour seems biased

The worker at the receiving end has to be clear about what the core issue is

I work on a contract basis in a large building that requires identification to enter. It’s impossible to know everyone there, but over the past year, I’ve noticed an increase in questions directed at me by staff members: “Can I help you?” and so on. They often seem suspicious of me, or even frightened. My response is to remain calm.

One incident was particularly troubling. I went to make some copies with my ID in hand and was asked a barrage of questions, including, “Why are you showing me your ID?” I answered in a stoic, monotone fashion that I