The article states that they needed to pay for insurance to do this, which they didn't do. It's a public park and if they want to turn it into a soup kitchen then they should also have to pay for it.
The park belongs to the community, and these people are choosing to feed homeless people using private funds in this park. The government should have the sense to use discretion when their is a technical violation of the law and consider whether the spirit of the law is being broken. Politicians and public servants are supposed to be a proxy for the will of the people, not dictators who decide what is proper behavior for themselves.