When I was young, we moved into a house my dad built new on an odd shaped lot. A triangular section of what had been our lot had been purchased by the neighbor, in hopes that no one would move in and conflict with the landscaping. This neighbor came over and told my dad how the landscaping should be done, so as not to conflict with his.
My dad proceeded to do everything the opposite of what this neighbor said.
Actually, it's that they want to enforce some basic standards to ensure property values aren't diminished because of the negligence of a home owner.
There are plenty of neighborhoods in the US that don't have neighborhood Associations nor HOA's.
It does, indirectly. It is perceived that a pattern of packages being left outside attracts thieves to the neighborhood, increasing neighborhood crime rate, decreasing property values.
(That's not to say that individual HOA actions in this area are reasonable or proportional, just that there is a nexus with property values.)
I think 99pi did a story on this about green lawns. They commented that a green lawn wasn't really a status symbol for yourself, but rather your neighbors. If you let your yard grow unruly, neighbors would come and tend it for you.
The idea is that owning a home and land was the american dream, this land was where you could do what you will. The ultimate self determination. However, the reality is, that your neighbors and the HOA just want to tell you how you will manicure your home. So in reality, people who proclaim self determination are enacting a socialist policy.