My interpretation of sitting in front of the door is either trespassing or at least interfering with someone's ability to get to a private property (from public property like a sidewalk).
From the article:
“When we sat down in front of the door at 8 a.m., about a dozen police squad cars flew from around the corner and piled out,” recounted Terry. “It was startling.”
“They at first gave us warnings, but we said, ‘We’re not going to leave because Planned Parenthood is the largest murderer of children in the western hemisphere. They’re trafficking baby body parts, they’re trafficking minors to kill their children,” said Terry.
So they were trespassing. I applaud their cause, but not their method. As the activist said, a small price to pay for saving lives, but a price to be paid nonetheless.