Kristin Cavallari’s friend Justin Anderson responded to Instagram trolls criticizing his decision to place his son for adoption at age 18.“To the people from private accounts saying negative things — go kick rocks on the freeway, you’re not welcome here,” the Very Cavallari alum, 40, wrote via Instagram on Wednesday, December 16. “We all have a story and as much as I believe our past doesn’t necessarily define who we are as adults, it definitely plays a role in who we get to be today.