Courts have already ruled on these type incidents…. NO it is not okay to shoot down a drone if it is flying above your property especially if it is flying in what is considered “public air space.” That is determined by local laws. Where I live it is considered 12 feet above the tallest structure on the property being public domain. If whatever you do is in complete view of someone/something in public domain then you cannot do anything about it. You can actually be charged if you perform any lewd behaviors within view of someone/something in that public domain.
If you shoot down a drone that is in that area considered public domain you can be charged yourself and might even be charged if you are caught doing something within view of a drone flying overhead.
Check your local laws because the FAA has been chomping at the bit to charge someone for this sort of thing so that they can get control over drones.