(Sodom, modern rendition)
There are four character types among people. One who says, 'What's mine is mine and what's yours is yours' is of average character, and some say, this is the character of Sodom. [One who says] 'What's mine is yours and what's yours is mine' is unlearned. [One who says] 'What's mine is yours and what's yours is yours' is pious. [One who says] 'What's yours is mine and what's mine is mine' is wicked.'
— Pirkey Avos
I was thinking today in the shull and afterwards about the statement in Pirkey Avos about midas Sdom. "What's mine is mine, and what's yours is yours" is an excellent negative law, for which all societies must strive. What was the problem of Sdom? They took this concept, which should be a negative law for the society, and enforced it as a positive law for the individuals: those were prohibited from giving tzedaka (we find in the passed week's parsha that Lot was almost sodomized by the Sodomites for sheltering the guests).
So, the problem is not the absence of social welfare — a healthy respect for property rights of the individuals — but the prohibition for the individuals to use their property to give charity. That is why Pirkey Avos has two opinions about this midda.
What about the character of the tzaddik: "What's mine is yours, and what's yours is yours"? Why can't it be "socialized"? Because when you socialize it, it becomes: "What's yours is mine, and what's mine is yours", a midda of a socialist... I mean, an ignoramus.
The character trait of a tzaddik ("what's mine is yours, and what's yours is yours"), in order to remain within its definition, must be that of a private individual. That is also what we should teach our children: When someone is visiting us, we share our toys. But when we are visiting someone else, we don't force them to share their toys; we respect their wishes about their property.