I disagree totally with their behavior. Sure they are young and not at home but please respect other cultures. Thailand is not Italy or the USA. They are a very calm culture. You can speak lower tones and still have fun.
Just remember this day and age with social media. it might not be this year, 5 years but later in life your interviewing for a job or political office. They start digging and see the disrespect you had for another country. Your past on social media will catch up to you.
Just be respectful of other countries ways. Thailand is a great country. Yes, I have gone there several times and respect them always.