Another reason might be that Thai mail order brides, in particular, are looking for relationships that local men can't offer.
It is utterly inappropriate to lose your temper with others.
Generally, expressing emotions on the public is considered to be an unfavorable behavior. They treat the elderly with huge respect and pay attention to bringing up children.
Although in Western culture it is common to meet ladies in bars, it's not where you are expected to find a Thai bride.
If you are visiting a country and want to find a bride, it's better to go to cafes, bookshops, cultural events.
Namely, Buddhism had the strongest influence on Thai culture and largely formed its traditions.