Preserving old buildings

Recently in Dallas, Texas, USA, a one-story building, built in 1959, in the Turtle Creek area was demolished by the owner. The building was designed by architect Harwood K. Smith as an office for Mutual Life Insurance Company. The site was purchased by The Canadian based Great Gulf development company. The plans are to build a high-rise at the location

Community activist and preservationist are upset the building was torn down and want the city to strengthen their preservation policy. There use to be private property rights in the United States. If the community activist and preservationist cared about this building why then did they not purchase the building? Instead of reaching into their own pockets they want the government to do their work to preserve a neighborhood, a building according to their values and not that of the land owner or other citizens. Basically these people are further proof of liberals trying to tell other people how to live.