"People of Color Don’t Go Outside"

On the lack of portrayal of people of color doing outdoor recreational activity in American imagery, BFP said:

erasure or denial of people of color using public outdoor land has many effects–first, and most importantly, it criminalizes our presence on these lands. It criminalizes people of color for being outside.

I need more explanations of the connection between denial of phenomena existing and what activists mean by the word "criminalization," I think.

On my "things to find literature about" list now.