They are. Facebook is absolutely telling the truth about this metric. 750 million active users in the last 30 days, 50% of that daily and 80% of 750mil weekly.
I don't mean to nitpick, I'm genuinely curious: how do you know Facebook is telling the truth about the figures?
I always assumed they were telling the truth because they're legally bound to (and because if they're caught lying, it would suck badly for them). I'm just wondering if you have any more info than that, since you seem so emphatic about it.
Okay, I'll spell it out for you in capital letters:
NUMBER OF USER ACCOUNTS IS NOT THE SAME THING AS NUMBER OF INDIVIDUAL PERSONS. THE NUMBER OF USER ACCOUNTS IS ALWAYS HIGHER THAN NUMBER OF INDIVIDUALS.
