The most important counterargument to address when speaking to the city council would likely be:
Keeping the park open longer would cost the city more money and funds might need to be taken from elsewhere to pay for it.
This is crucial because city councils are typically concerned with budget constraints and resource allocation. Addressing financial implications demonstrates an understanding of the council's priorities and allows you to propose solutions or compromises that could alleviate financial concerns while still advocating for extended park hours.