I think it's simply people don't understand Thai culture. There is nothing wrong with the culture, it's just ... well different to the culture you/they come from.
it stems from indirect communicative style, which has as many advantages than disadvantages, like the direct style in countries, especially Germany and the USA.
I keep seeing posters mention 'Thainess' as if it is something negative, it's not, it is taught at schools here and personally, I admire it.