I just activated the option to copy posts from facebook and was surprised to see it posts their full name. That is a huge privacy concern. I disabled it in the mean time, but it should have some option to either display their first name or initials only.
I see your concern, but you have to know that this information is public information from Facebook (!). See here for details. That doesn’t mean the plugin should take privacy equally lightly, so I will put an item on the requested features list to display only the first name (initials cannot be retrieved from Facebook as far as I know).