For racism in Thailand, I think Thais love of white skin does not come from their racist ideas of people with dark skin, some Thais do harbour racist thoughts towards their neighbours. I have many friends who will tease their friends that their home country is actually Cambodia or Myanmar.
Also, when the Rohingya refugees fled Myanmar, a lot of Thais defenders their PM's decision to not allow them on Thai soil. Some Thais tended to generalise that these "invaders" were liars and thieves.
Thailand is a very patriotic and nationalistic country, and can sometimes be fearful, xenophobic, and have lack knowledge of other countries, including their neighbours. Saying that, Thailand has a 65 million population, so you will find people from one extreme to the other.