The "Eject" button
Putting the "delete your account" button up front is Facebook's "money-back guarantee," sort of like if you purchase something online, there may be a 30-day trial period. You're not under any sort of obligation to keep it if you're not happy, and the policy shows that the company is not trying to trick you into using or keeping the item or service. If you want to bail, your method of getting out is right there. You have the choice.