I think you missed the point,
The "Like" button is a powerful commercial instrument. If you've worked with the FB API you'd know what data-mining you can do with it to find out things about your users. Namely - what they like. So you can try and sell that to them. Compare it to Google ads - super-sophisticated backend algorithms trying to figure out what you are looking for by analysing your recent browsing and the massive history and profiling they keep about you (because every website has google ads so they can follow you through the internet) - all so that they can serve you just the right ad.
And here FB comes along and just *prompt* you to tell them what you like! How simple - and we do it. Not only that but that comes free with who you are, where you live, who your friends are, what things interest you and a whole wealth of information about you. Without not a fraction of the computing power and algorithmic sophistication that Google needed to invest to reach the same result. There is a reason why Google were upset with FB when they came out with the embeddable Like button, why they tried to compete with the +1, and why next to SEO companies talk about FBO as well now.
The "Want" button is just the next logical step up from that. The reason I hate it and mock is because it's so obvious. With the like button there was an element of "social" "niceness" to it and you could argue that its roots where in social interaction rather than commercial opportunities. With the "Want" button they will basically drop the act - tell us what you *want* so that we can try and sell that to you. Seriously, what are the masses going to click *Want* about? World peace? Or that latest gadget from company X? They might "Like" all sort of things every now and then that don't directly give you meaningful information for your company's commercial efforts. The "Want" button weeds away the funny comments and silly videos and gets right down to what people *want*.
So yeah, they might create a "Support" button along the way if it's not any additional hassle and doesn't clutter the UI or takes your attention away from the "Want" button. But they couldn't give a toss about it. Unless of course it turns out that they can sell the information to politicians, in which case they'll add it with friggin bells on.