Well I think, but don't know, that Russians get treated very well by the government here in Vietnam because of all the assistance Russia provided during multiple major armed conflicts that I am sure you have heard of that took place here.

Thailand unfortunately are just kind of jerks about their visas towards everyone. They spend a bunch of time luring in particular demographics, then the plan works, then they act like they don't want them there and create new prejudices so that the very thing they set up, becomes something that they are actively discouraging. Then the complain about not having enough tourists. They are a truly strange country in regards to that.