Some community - I wonder how many of his neighbors bothered to try and befriend this lonely old man? How many times they had invited him into their homes for dinner? Offered to pick him up something at the store? Offered to help him fix up his place?
Apparently, their idea of "community" was to gang up on him and get the government to seize his home. Real neighborly.
You're essentially claiming that what you do on your own property cannot possibly effect my property rights. However, by your formulation, my exercise of property rights includes the right to do with my property as I will, include selling it. The question then is, in that situation can your exercise of property rights possibly have an impact on me?
Putting it that way, yours is clearly a false premise: the condition of your property can indeed affect my ability to dispose of my property as I see fit. The condition of your property enhances or degrades the market value of my own, and makes my property more or less saleable.
In that case, your actions on your property obviously can affect my property rights, in the sense that they affect my ability to dispose of it as I will. IOW, your property rights and mine are not independent.
Things like that are the basis of the valid concept of "community interest," which can and should act as a constraint on the unlimited exercise of property rights.