If they're not going to enforce it I want them to remove the sign! Why is that controversial? and, ideally make it legal to bring your pet?

Maybe we should just ignore all signs? "No Tresspassing", "Employees Only", "No Parking", "No Stopping", "No Dumping", "No Fishing", "STOP", "Do Not Enter", "One Way"

I agree with the sentiment and think we don't do enough that way. However, sometimes laws (rules in general really) exist for broader reasons and there are edge cases where they don't make sense. In practice carving out every last edge case would be quite difficult and time consuming.

There's a park that closes at dusk. I walk my dog through it in the early morning hours unless I happen to see police hanging around. What's the alternative? The local residents clearly don't want people partying or sleeping in the park at night due to the crime that would invite in nearby areas. No one cares if I walk my dog through it. I doubt I'd be successful if I tried to effect change. What new wording would I even propose?