That may be so, and Im sure that people who get off on porn agree with you. However, there is no reason that the desires of People for Porn should trump the desires of those who do not wish to have it shoved in their faces and the faces of their families. Citizens, acting in concert, have a great deal of discretion in managing their environment. They do it all the time in regards to zoning laws, the construction of public works, public nuisance laws, environmental regulations, etc. Before the passage of many of the environmental regulations we operate under today, many people argued that government did not have the power to regulate pollutants. That is no longer an argument that holds much credence. Today, the argument is over the efficacy of those regulations and in discussions of cost/benefit relationships.
Thanks to the intellectual pollution that inundates our society, I predict that a backlash is coming, there will be regulation of intellectual pollution, and the discussion in the future will be in the cost/benefit relationships.