It sounds like they’re walking the dogs on a basically public nature trail that runs through Prince’s property. In which case, in the abstract, I am fine with dogs being off leash.

This is one of those stories where it’s impossible to take a side without accurate context. It could be that the dogs are actually menacing, it could be that Prince isn’t happy about an easement on his land and is using this as a pretext to harass people who rightfully use it to walk.