Absolutely not incorrect because obviously you won't pay taxes if you paid taxes already and it has been subject to DTA rules. It's very easy to understand, if you paid taxes already somewhere, you won't pay in Thailand, if you didn't, you will be taxed - DTA won't change that.
This statement is also absolutely correct, it just doesn't address whenever taxes have been paid already and if there is a DTA.
"There is no difference in where it is sourced anymore and it doesn't matter if it's dividends - if they are brought to Thailand, they will be taxed. "