You might want to take those numbers with a grain of salt. As per the comments in the thread, many of them are incorrect and/or stated in the wrong way (percentages rather than "round to nearest X").

Something else to keep in mind is that in most countries tips are generally only given in the case of (well) above-average service, rather than as a matter of course like they are in the US.

Just from eyeballing the countries on that list I have spent enough time in to know the locals, the numbers are nearly all well and truly higher than I've ever seen any of them tip. My impression is that list is either a) coloured by and for American expectations and/or b) created by consulting the people being tipped, rather than the people doing the tipping.