who are you to tell someone what they can and can't do with their money after they die?
There are plenty of limitations on what you can do with your property. You cannot use it to kill people, for one thing (unless you are a government or a corporation, but even than it's usually illegal, it just gets swept under the carpet). Try buying a nuclear bomb with your money. Heck, try buying drugs.
So there are legal restrictions. Then there are moral restrictions. Let's say you want to buy an island full of people and have it just for yourself, so you buy it and sweep all the inhabitants into the ocean. Or send them off on rafts. Would you argue this is a legitimate use of your property? In fact, this kind of thing happens all the time, except with houses rather than islands. But governments have done exactly that with islands, too - google Diego Garcia.
The issue is emphatically *not* about whether there can or should be limits on using your property - because there always have been such limits, and for a good reason. The issue is only whether a particular new restriction should or should not be introduced. That can be decided on a case-by-case basis, not through groveling against your little property god.