What about noise polution? What about cars on blocks making the neighborhood look ****ty and bringing your property value down? What about not mowing your lawn such that grass gets high, and rodents get numerous, and the neighborhood looks ****ty, and property values fall? What about lawn chemicals that run down hill onto your property? What about people who don't kill off the dandelions and that **** spreads into your lawn. What if your neighbor goes to work at 4am and revs his very loud truck several times before he leaves? Is it harm if it bothers some people and not others?
My point is, "property rights" can be grey in terms of whether they think there is harm or not. Not black and white. Neighbors can be great and horrible. Where do you draw the line between great and horrible? Acceptable and unacceptable? Actionable and not actionable? Different people draw that line in different places. Libertarian's NAP seems pretty good at solving the clear-cut black-n-white issues. Not so great with the grey areas, when "harm" is less objective. There isn't a magical formula that gives the just answer in every situation. And you may not get what you think is just.
Seems to me, in cases like these, even the most ardent libertarian can support him some big government telling other people what they have to do and what they can't do on their property.