On Wednesday morning, several hundred protesters were gathered. They listened to speakers who decried the cruelty of the administration’s indiscriminate crackdown on immigrants. They waved to families heading in for appointments, and offered them groceries, teddy bears, and Easter baskets as they emerged. “Watching the news, I felt like I had to do something,” said Lauren Baker, a 23-year-old music instructor who has been coming here every week for three months. “What, am I going to sit at home? This is where I’m supposed to be.” Last weekend saw an estimated 8 million people take to the streets — 180,000...