The founding fathers believed everyone has the right to life, liberty and property. Libertarians believe in a minimal governmental presence regarding private property as landowners have rights to defend such property against intruders and against eminent domain. It's a free world and a free market--what someone does on their own property is their business. That's why it is called "private property."
The libertarian idea that individual property rights should be held in the highest regard is misguided. While property rights are important in any free capitalist society, the government needs to play a role in land usage as well. When the rights of private landowners are allowed to override all other concerns, it can be very difficult to develop infrastructure for the public good, such as roads and public parks.