Facebook has so much power with censoring only one side of the extremists. A good experiment would be if you could find a Christian priest to report, and check whether their response is weighted differently.
Data that Facebook is fighting hard to make sure people can't collect. Just like how they were poisoning the well while suing academic teams just trying to get information on ads data.
That would be an anecdote just as Ahmed's findings were anecdotal. It you want to check for bias you need data.