If we stumble upon a profile with only FindAGrave as a source, why not just do a quick look on FamilySearch for another source and add it? Or look at the memorial to see if there is headstone and other valuable information. Some FindAGrave memorials are indeed, poor qualilty, but many are a treasure trove of family information including full obits, copies of death certificates, mentions of occupations and places lived, community involvement history, family members names, etc. etc.
Often when sourcing, I find profiles that the previous edits where only to flag it as unsourced, even inserting "source needed" in several places in the biography section. In just a few seconds more than it took someone to do those edits, I clicked on that little [1] on my tool bar and a FamilySearch census or marriage record pops up, that I can add to the profile instantly.