People seem to have this attitude that once they discover a few incorrect findagrave memorials, that it no longer deserves to be a source. Or the person responsible for a memorial doesn't respond or won't change things.
I have been working on wikitree findagrave suggestions for a year now, and I only add a findagrave memorial to a wikitree profile when someone originally cited findagrave as a source, and I am sure it is the right person with matching dates. I have maybe done 1,000 or more of these missing findagrave memorials, and very rarely (1 out of 100) do I find that the findagrave data is out of whack with other sources. If possible I look for additional sources to add to the profile too because ONE source is never good, no matter what the source is. I never change the dates or locations without looking for additional sources, but here is the rub, sometimes a wikitree profile ONLY has findagrave as a source! All the searching in the world just gives you a gravestone, or worse a findagrave entry without a gravestone. Do we not allow that in wikitree?
So I agree we should always verify with other sources, but to ignore the millions of memorials on findagrave seems like a mistake. Is it any better or worse than the Census data? I see mistakes in Census records all the time, should we not allow Census records? What is next?
And I have made 500+ suggestions to findagrave for changes, connections, and corrections, 95% have been accepted, some very quickly, some automatically. Which means to me that the data is only as good as the people adding the data, which I find no different that wikitree at times. Maybe the findagrave contributors aren't doing the research as much as we do? Who is to judge?