"It hardly needs to be said that plaintiffs' food-sharing programs benefit the public interest," Yohn wrote. "Despite [the city's] considerable efforts, many Philadelphians remain homeless and hungry.
"The governmental and private programs that minister to needy Philadelphians are largely overwhelmed and clearly insufficient to meet all their needs," Yohn added. "To impede plaintiffs' efforts can only harm the public interest."
Homeless advocates estimate that 175 people live outside along the Parkway between City Hall and the Central Library of the Free Library of Philadelphia.
City Solicitor Shelley R. Smith said federal law gives the city the right to appeal Yohn's injunction: "The fact that we exercise that right doesn't preclude us from sitting down and talking."
Paul M. Messing, the Center City civil rights lawyer who, with the local chapter of the American Civil Liberties Union, sued on behalf of the religious groups, said he hoped the city withdraws the appeal and "addresses the short and long-term issues."
"This is an attainable goal," Messing said. "Mayor Nutter has done a great deal for the homeless and I think he can be the first American mayor to end homelessness in his city."
Yohn's preliminary injunction lets the groups continue providing food to homeless people without penalty until a final civil trial next year.
That timetable could be delayed by the appeal, although it is unlikely the Third Circuit Court would dissolve the injunction while it was pending.
Although Yohn affirmed his earlier oral order blocking the feeding ban, he left in place city health rules that govern licensing and regulation of the manner in which groups feed homeless people.
Nutter's regulation, which bans public feedings of groups of more than three people in any city park, took effect June 1.
Administration officials argued that the public feedings on the Parkway - part of the 9,200-acre Fairmount Park - rob homeless people of dignity, have the potential of spreading food-borne diseases, and degrade the park landscape through overuse, trash and, at times, human waste.
Nutter said that as a transition, the city would let religious and homeless-services groups distribute food on the concrete apron in front of City Hall's north portal. At the end of a one-year transition, Nutter said, all homeless people would be fed from at least four indoor facilities around Center City.
Yohn, however, agreed with the groups challenging the ban that there was no evidence backing the city's reasons for it. He wrote that the City Hall apron was not an acceptable alternative.
The four groups - Chosen 300 Ministries, Welcome Church, King's Jubilee, and Philly Restart - sued, contending the ban violated their First Amendment right to free exercise of religion.
The groups' representatives testified that they had taken the city's free food-sanitation course and follow it in feeding the homeless, and clean the area before and after the meals.
But the groups insisted they have a constitutionally protected and divinely directed mission to minister to homeless people where they live - outside on the Parkway.
"A preliminary injunction will not cause [the city] serious injury," Yohn wrote. "It merely restores the status quo that has existed for more than two decades. That hardship is clearly not greater than the hardship plaintiffs will suffer if the ban is enforced.
"Finally, there is a strong public interest in protecting the free exercise of religion. Plaintiffs' food-sharing programs benefit the public interest."
Contact Joseph A. Slobodzian at 215-854-2985, firstname.lastname@example.org, or @joeslobo on Twitter.