No one on the original series ever said "damn." Not McCoy, nor anyone else. It wasn't allowed. They had to fight Broadcast Standards and Practices to allow Kirk to use "hell" as an interjection once in "The City on the Edge of Forever." (It could be used to describe a mythical place, hence the use of it in "The Doomsday Machine," but that's it.)
There's also Lazarus saying "I'll chase you to the very fires of Hell!" in "The Alternative Factor," Kirk quoting "Better to rule in Hell than serve in Heaven" in "Space Seed," McCoy describing Tombstone as "Hell-for-leather" in "Spectre of the Gun," and Kirk referring to people's "private hells" in "Requiem for Methuselah." Which is more uses than I thought.
Chakoteya's transcripts claim that Krako says "How the hell'd I get here?" when he's beamed up in "A Piece of the Action," but I checked, and it's actually just "How, ha-how'd I get here?"
McCoy used "damn" quite a bit in the movies, as did many other characters. But never, not once, on the TV series.
Kirk did use "damn" a couple of times, but not as an expletive -- "The evidence... was damning" in "Court Martial" and "I can't damn him for his loyalty" in "Journey to Babel."
The only reason people think otherwise is because of the proliferation of "Dammit, Jim!" memes. But those are all from the movies.
The one and only time that DeForest Kelley's McCoy (as opposed to Karl Urban's) said "Dammit, Jim" was in
The Wrath of Khan -- "Dammit, Jim, what the hell's the matter with you?" I think the meme comes largely from Dan Aykroyd in classic the
Saturday Night Live Trek skit, where he said "Dammit" twice. And I suspect its association with "I'm a doctor..." may have originated with a T-shirt slogan, which I suspect is where the "Beam me up, Scotty" meme came from too.
And I laugh every time someone says that Trek used to be "family friendly," and hoo-hah, was it not. They were constantly pushing the boundaries of what was allowed on network TV of the era, including that use of "let's get the hell out of here" in "City" (which was way way way more "edgy" and "controversial" on network TV in 1967 than Tilly's use of "this is so fucking cool" was 50 years later on a streaming service), as well as near-constant pushing of costuming boundaries. It looks family friendly now because standards have changed.
Exactly. It was specifically created to be an adult drama, and Roddenberry made it as sexy and racy as he could get away with. It's just that censorship was far more strict then, so even the most adult shows seem tame by today's standards.
It's like movies. When the Hays Code was in effect prior to 1967, all movies were equally restricted in their depiction of sex, violence, profanity, etc. But then they introduced the MPAA system that allowed more adult content under the R rating or above. With TV, the FCC restricted adult content on commercial TV, but subscription cable and satellite TV was free from those restrictions and able to feature adult content, and that led to the climate we have today where a lot of shows have graphic violence, language, nudity, etc. and shows that lack those things are seen as family-friendly. But it used to be the norm for everything, no matter how adult the target audience.