Maybe. Don’t get me wrong, I love the Medium writing experience (although I and many others hate what responding like this does to my Profile).
But if Medium is all about ‘come for the writing tool, stay for the network’, all Facebook has to say is “‘”we’ve got a similar writing tool now, and our network is HUGE”.
Which is exactly what they just did.
Medium needs to respond, quickly, with a better narrative. Something to do with privacy and advertising, I expect.