Michel,
I do not claim to own the profiles I start, the question is one of policy and etiquette- whether he should add a link to a Find a Grave Memorial without checking for accuracy, rather then whether he can. As a new member I asked him for the courtesy of time and space to develop these profiles of near kin stage by stage rather than having to practice new Wikitree specific skills on profiles of people further out that would be harder for me to keep track of. Second great grandparents may seem a stretch to some, but I was raised to pay my respects at their graves and have 5th great grandparents in that cemetery. When there are so many generations of a family piled up in one town, care must be taken to sort out the records of all the fathers, sons, uncles, nephews and cousins of the same name by sorting all the records of their siblings, wives, and children.
Being 12th generation Massachusetts born and bred, I am well aware that I do not "own" my ancestors, but my patience with people who ignore provable facts in favor of legends and rumors grows thin from time to time. I have immeasurable gratitude for the managers of the Mayflower and Puritan Great Migration Projects in particular, who are dedicated both to patient and meticulous research and defending the integrity of those profiles. I have great respect for Ellen Smith and Carol Baldwin as well, for their wide ranging efforts on Massachusetts more generally. I have collaborated with several other people, it is just this one specific behavior that I find annoying because it runs counter to what I've understood to be widely accepted practice and proof standards of genealogical and historical research.