Are nations going to publish a list of 'good' words that we can't get sued for using, and name it 'neotalk'?
Of course, new chrome extensions can pop up faster than FB's legal department can respond, so the mere existence of other people that haven't been caught yet is not evidence of selective enforcement.
Now the morality of this behavior is an entirely different discussion...
(In essence, the argument is not a technical one: it is only interesting in that it changes the dynamics of "could someone have been confused"; if people see the word "Facebook" as a moniker on products all the time that are not made by Facebook, then clearly they are not going to be confused by any individual one.)
And basically, that's why most trademark lawyers will act on even the smallest unauthorized trademark use - they do not want to leave it to chance.