Only because Kirk hadn't banged them yet.

In TOS Kirk really leans into not interfering with the “healthy” development of a civilization. If it isn’t healthy in his judgement, he interferes. So, essentially when it comes to Kirk if it offends his sensibilities he assumes free reign change it while paying lip service to the idea of non-intervention.

Yeah, but in TOS we also see what happens if you forget a book about the chicago mob of the 1920s on a developing planet.