Sure you are unlikely to be targeted specifically, but once someone has decided to commit identity theft, you don't want to be the easy target.
And 10 FB users or 300 million is kinda irrelevant with all the automated tools/scripts that are available these days - searching for the 1 vulnerable person out of 300 million is a relatively trivial task. They will 'stumble' upon your profile not because they randomly picked you from 300 million, but because they ran a script that identified you as an easy target.
But it's just my opinion, I don't actually know. Maybe one day when I'm being carted away for ordering a million grandma porn videos without paying, I will realise the error of my ways...
There's a reason companies are trying to scare you about identity theft. They're in this market because they see it as a growth market. They believe identity theft will increase and they're targeting it with their services and products. I agree that some will use scare tactics to get us even more wound up over it and make some extra $, maybe because they've already over saturated the market, however I definitely think it's going to become a sizable problem.
Worrying about identity theft is as rational as worrying about getting your eyes gouged out by crow - yes, it can happen - but fact of the matter is that it's not very likely to happen.