
The thumbs-up sign originated in the gladiatorial days of ancient Rome. The crowds in the amphitheatre as well as the emperor himself indicated whether a gladiator should be spared (thumb up) or die (thumb down).
I wonder if the people in the photographs are aware that their antics are associated with such extreme violence.
There is an alternative, simple and less aggressive gesture you can use to show your approval of something.
Connect a forefinger and thumb, leaving a circle between them.
David T
Chon Buri