If that’s what’s holding you back, don’t worry. Thai people are very chill and kind on the whole. Also the economy is very dependent on tourism, so dealing with westerners is part of that. And, the US has not fucked Thailand over anywhere near as much as the surrounding countries (vietnam & cambodia, mostly, but even those folks are extremely gracious). People will appreciate you if you are kind, polite, and try to follow local customs.