That said, I am in the minority of gamers/mobile app users. I am incredibly paranoid about security, I like ingenuity and vibrant pixelart, and I don't have a personal Facebook page. The vast, VAST majority of users are not like this. They have Facebook, Twitter, Instagram, Whatsapp, Skype and IM5 accounts, and love posting stuff on them. They like getting free stuff, they enjoy eating fast food and they want the table set for them. That is not a judgement or an indictment, it's just an observation.
You need to identify your user base, first and foremost. Do you want to make a game that will excite the people that actually frequent gaming forums, or do you want to create something that the general populace would like to play, and tell their friends about from their Google+ pages? Do you want to target stay-at-home moms that use Pintrest all day, or do you want gearheads that hang out at the Advance Auto Parts store down the street? Do you want teenagers playing it in class and getting in trouble for it, or do you want hipsters to talk about it at cocktail parties during GDC week? I don't want to jump on my soapbox again, so I'll stop there, but the first lesson of Marketing 101 is: Know Your Audience. If you are looking for users from the TouchArcade forums to buy your app and they don't like Facebook, then you have your answer. If you aren't making the game to appeal to them, then don't worry about what they have to say.
For the record, I plan on implementing the option in my future games, to post a screenshot and score to Twitter. I haven't decided on Facebook, only because I don't think the juice is worth the squeeze. The folks that would play a game I would make probably aren't all about Facebook, and just keep a page so they can stalk their exes. If you believe that you'll profit from using Facebook and incentivizing users for providing positive reviews of your games/apps, you should do it, despite what the hardcores in the gaming forums think. Yea, you might not get a review from Touch Arcade, but there is always Slide to Play, 148Apps, IndieGames.com, SlideDB, DroidGamers, TIGForums, and hundreds of other places to publicize.