I lived on Koh Samui with my Wife 20+ years ago and while it was a delightfully beautiful place ( really. Breathtaking in places ), between the rip offs , bad water when they had it and we lived in what looked like a nice place, Santi Thani ).
I remember road blocks with the thai police looking in cars for weed and other drugs and always waved me on when I was with my Wife returning from one of the great restaurants that exist there as I speculated that a) I was obviously not high ? and b) my older age ? ( mid 40's at the time )
In any event, heed the warnings.......and strictly in my own opinion, life is too short to support places that do not support us back