There will always be ignorant people who "ruin" the hobby. It comes with almost any hobby I think.
When I first heard about geocaching, I HAD to do it. The only problem I faced was that I could never afford a GPS. I registered on this site in 2009. I found my first geocache yesterday...5 years later. I was ecstatic when I saw there was an iPhone app. I would always come back and check every few months and just the other day, I found there was a free app so I downloaded it. I asked my husband to join me and we ended up having a lot of FREE fun. I do plan on purchasing the full app and membership when I have the extra funds. I'm a new mother and wife so I'm on a strict budget!
Anyway I think that once the newness of the free app wears off, things will calm down a bit. If you don't like who is hiding a cache, just don't go looking for it. Maybe do a bit of research first. Maybe there could be suggestions to make the app very limited like, after you click on 10 caches, you can't click on anymore until you buy the app.
I also saw on the news where some guy is hiding money in caches in San Franciso I think. The news also said that it's catching on and is happening all over the place now. I think once ALL this media coverage goes away, people may not be interested anymore.
Just a thought and my opinion