I was always under the impression that the reason you couldn't undo was purely to encourage putting thought into your votes, instead of clicking after the first sentence, getting through the rest of the post, and looking to take your upvote back.
Guess I was wrong. I'd say 30 seconds should be enough, with this thought in mind =]
Yeah, tell that to the guy who wrote "ISIS beer fund" on his PayPal transfer to his mate that we have an "independent judicial system".
No - we have an outsourced judicial system, where Facebook and Google will spy on you more than the USGov, the bank will control your money more than the Government, and the insurance company will have you in an autonomous car faster than a mandate will. That's modern neoliberalism.
Because being able to call someone a terrorist (or a hacker, in 5-10 years time) as a reason to turn off their credit card when it's the only method of payment left will be a dystopian nightmare.