The American cemeteries are under control of the United States. WE cut the grass and tend the graves. The land has been given to America in perpetuity by the French so our servicemen lie in American soil. The responsibility is ALL ours. Have you visited the WW I AND WW II cemeteries? I have! I’ve even visited our fallen in Belgium, Luxembourg and elsewhere.
If you had ever seen the thousands of French schoolchildren carrying bouquets to place on American graves, you would not be so dismissive of where they rest in peace.
In fact, I have visited American military cemeteries in Europe and have seen the children (and adults) there paying respects. The people of Normandy seem especially appreciative and respectful toward American visitors - perhaps they are better attuned to what occurred there, than are the people of Paris or Brussels. The cemetery at Colleville-sur-Mer is perhaps the most breathtaking piece of land along the English Channel, though I hesitate to think of it as "given" to us. The price paid was very high indeed.
Please do not think me dismissive of our fallen soldiers' resting places. I truly do wish that they could lie undisturbed in perpetuity, but the people who are destined to inherit those pieces of land called France and Belgium are not likely to care one whit about land use agreements made by a bunch of long-dead Christians.
IIRC, British military cemeteries in France have already been vandalized. I suspect it will gradually become a regular event, much like the car-burning street festivals. Unless something changes drastically, I think we can expect our memorials and grave markers to be treated similarly. And, as you noted, the responsibility is all ours. So how do we deal with maintaining such sites in lands that are increasingly hostile toward us? We've seen repeatedly that the local gendarmes will be restrained in dealing with these "protected" people - just look at the mess that is tolerated in Calais.