The episodes seems to be Miri had a crush on Kirk. Kirk didnít reciprocate but did not immediately dismissed it either.
I actually see Miri as an extension of Kirk protecting his ship and his mission.
Kirk was not interested in any sexual relationship with Miri but knew he needed her cooperation to succeed in the mission.
So while Kirk didnít reciprocate as it would be immoral. He certainly didnít shut down any her attraction because he needed her help
The episode wouldnít fly today. However I actually donít think Kirk did anything immoral because he didnít reciprocate their relationship
I also find the joke ďnever interested in older womenĒ funny as well