Looks like both you and the cache owner did your homework. Your note would have been better served as an email to the owner. Noting that the finders are having an impact on the area is important information for the cache owner (and groundskeeper) to have. That way they can adjust the hide or archive it if needed.
That said there is nothing whatsoever inherently disprespectful about a cache inside of a cemetary. Some cachers have mentioned having a cache on their market when they pass. Reality is we bring our own thoughts and ideas to the table. When I watched the movie "Australia" I was suprised to see a note for Aboriginies saying the names of the dead were mentioned. They explained it in the movie and I understood. Jews will place a stone on a grave as a sign of respect. That doesn't strike me as something I would do to be respectful. I'm more inclined to pause in thought, but both are respectful.
Something to ask yourself. Where does the edge of the cemetary begin? I dont like stepping over someone if I know they are under ground. 2' over I don't mind. Thats my 'edge' and it has nothign to do with a fence. Our local cemetary has fenced off about 2 acres of open space for expansion. The fence is an artifical line that doens't have a lot to do with where sacred or respect starts. However in your case it does appear to be where your personal line starts.
It would pay some dividends to search your soul and better understand why you feel the way you do. Then when you are out in the world where you may be passing near, over, or on top of where someone died and it was unmarked lost in the sands of time (like at your fishing hole) you can at least understand why it's ok that you are not paying your respects there, where you do when you know and why that's ok.
Jews?! Are you Jewish? I take offense to the way you phrased the colloquialism.