I agree most of them do have a hard ‘T’, but “talwar” (I’m guessing this is the word you’re referring to) is pronounced with a “th”. Probably the words for “firecracker” (pataka) or “holiday” (chuttee) are more representative.
If by “brought about positive changes”, you mean that it’s allowed colonial powers to enrich themselves enormously while draining their colonies of wealth, leaving millions to starve and destabilizing regions for generations, then yes perhaps you’re right. The argument you used could be applied in exactly the same way to justify slavery. The positive changes here always favour the oppressor, never the oppressed.
Thailand = Thighland, says Trump apologist/convicted felon (lemmy.world)
Dutch king makes historic apology for his country’s colonial past (www.politico.eu)