So there must've been enough evidence to convince a judge.

They swept up citizens, involved in gangs, with outstanding warrants. So its not clear if they have defaulted on warrants, in which case they would not be eligible for bail, or whether these are warrants the police haven't gotten around to serving, in which case the suspect can be back on the street as soon as they are arraigned.

GANG-FOCUSED WARRANT SWEEP LANDS 50 BEHIND BARS
...The operation, a proactive warrant sweep, was conducted in communities recently impacted by gang violence. The mission of the operation is to dismantle violent activity by arresting individuals in those areas who are wanted and negatively affecting the quality of life in their respective communities.

The goal of Operation PAWS is to send a clear message to individuals involved in gang-related activities. . Individuals who are believed to be involved in gang activity were the primary targets of the sweep. By locating and arresting such individuals on outstanding warrants, the department also seeks to reduce gang violence and augment the level of intelligence necessary to prevent future gang-related hostilities.