From a few simple searches on the web it is clear this man is zealous about selling his trade and broadcasting his character and point of view to any possible reader.
He has a forum which sadly is rather devoid of interaction & conversation, unless you think that posting numerous items from & about yourself... to yourself, equates to effective communication. It's titled "American Thai Ridgeback Association" or ATRA for short and although it's colorful and vivid, anyone reading the forum will quickly get a flavor of his difficult and troubled character, as anyone who has called the phone number will testify that he is a difficult individual to discuss or converse with.
So this is the "Mr Nice Guy" side of Sterling.
But talk to any shop / service provider that he has a need to do business with in Chiang Mai and quite a different side will be revealed. The true Jack Sterling. Don't mess with this guy unless you need constant bombardment of phone calls or email delivering rantings of what can be interpreted as coming from a troubled mind.
Some store keepers actually shudder when his name is mentioned and quickly lower their voices for fear he might be able to hear them. Some are openly frank about his attitude. They will speak about his loud, aggressive and threatening language and about how their staff feel insulted and afraid of him. Some business people will add that he has been banned from trading with them and that he not only has a bad mouth but bad credit too!