If you come to live here in Thailand for any sort of extended time you are going to fall into a group of locals, probably at a bar somewhere, who is going to have a few members who are quite jaded about the entire expat experience.
Normally these people spend more time at the bar than they do anywhere else and they have mostly negative things to say about almost anything that Thailand does. They believe that Thai people for the most part do everything incorrectly and that they are being ripped off all the time because Thai people don't like foreigners.
I don't believe that this is the case at all. I think that maybe Thai people don't like this particular person, but as a whole, I have found Thai people to be some of the most welcoming people in the world.
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it's called the "Land of Smiles" for a reason and from the brief experiences I have from living here I would say that it isn't very often that you will meet a group of Thai people that wont return a smile. People here seem to get great joy out of very small things and for the most part, I think that Thai people are very ready for a situation to become humorous and get a great deal of enjoyment when exactly that happens, regardless of how old they are.
Now there are times when Thai people might seem a bit shy of you but this is just the language barrier talking here. I know that I am also shy to approach Thai people because my vocabulary isn't very good yet, and likely never will be.
I think it is unfair for the people that I know at the bar to presume that they are hated and being ripped off all the time when it is more likely that they just don't understand the situation and when that happens they lose their cool and therefore, people want to stay away from them. This would be true in any other country as well.
You've likely heard about "losing face" and how it is a really bad thing in Thailand. This is why you rarely see emotional outbursts in public here. No matter who is in the wrong, if two people have a shouting at one another in public, both of them are looked down upon. I'm not saying that nobody ever loses their cool, because they do, but for the most part I feel as though Thailand is much more friendly a place to be than most of the western world is. Certainly a lot more friendly than my home country of the United States which I believe to be many times more dangerous than Thailand is just in a general sense.
So the answer the question is that no, Thai people do not hate foreigners. I'm sure there are some that do but there is no widespread hatred towards foreigners based solely on nationality. If you act like an asshole you are probably going to be treated like one though - just like the guy I know that is constantly bitching about Thai people in the bar. He deserves the attitude that he gets from some people and I am sure there are plenty of Thais that hate him but generally speaking I don't think there is much xenophobia in this country at all. I certainly haven't experienced much of it.
I actually think that Thailand, well, aside from government officials, could be a benchmark or a lesson to be learned by the rest of the world about how to treat outsiders. You will almost always be welcomed into any situation and I have even been just riding my bicycle down the road and been invited to go have drinks with complete strangers. I didn't stay for long but they didn't have any ulterior motive; they just wanted to give me a drink. Where else in the world are things like that? It certainly isn't like that where I come from