I get annoyed by over-taping as well, it seems like ugly pollution waving in your face. My pockets are always full of crap by the time I get home, and sometimes it contains excessive flagging.
I go fairly sparse when flagging, especially when route is going straight or is obvious. I put more at corners. I also don't leave huge long dangly things. In wilderness areas, like Spindle, etc. I always retrieve my flagging when coming down, so the next explorers can have the same route finding experience that I did.
I guess your reaction on facebook reflects the type of users. Higher levels of experience leads to wanting more than trudging up and down.