Some unthinking people love nature as toddlers love kittens and ducklings: someone responsible has to watch over them, preventing them from destroying what they admire. Buying a pristine spot because you can and then turning it into city is a form of destruction. Visiting and leaving litter is as bad, but more common.
Sightseers are the pioneer litterbugs, settlers finish nature off. Still, we have to escape the madding crowd. Bigger numbers, more Lebensraum.
The insensitive sorts are following their noses to the last pretty spots on earth. Every secluded residual bit of nature awaits its fate. Some idiot will decide to do something special there. Those with resources can often do better in this competition, without necessarily knowing better. The moon and Mount Everest are said to be covered in more human litter than human tracks.
Curb human population growth or ruin the planet. Hong Kong type high-rise accommodation can go so far before city fathers have to succumb to the inevitable of invading the remaining adjacent green. Humanity is approaching suffocation from its own excess and bad habits.