I'm on your side on this one; but you should know that when I'm in BKK I always connect at 100 MBPS, over ten times faster than I can here in Kansas City.
To be fair the last time I've been in BKK was like 4 years ago and I am more familiar with Koh Samui than I am with BKK. It's definitely possible that there have been some huge improvements in Internet connectivity there. China had some HUGE improvements in its Internet infrastructure in the past few years, though it's not quite at the level of HK yet.
Though one thing I should caution though is just because you connect at 100 MBPS doesn't mean you'll get 100 MBPS of international bandwidth. It may simply mean you get 100 megabits with sites located in Thailand while the international link itself is slow and congested.
If you ever swing by to HK I'll buy you a beer!