The entire mission of this episode is to repair the cultural contamination done to the planet by the Horizon leaving behind something they shouldn't have left behind. And in the final scene when McCoy realises he left his communicator down there, and Spock rightfully points out how serious that could be, Kirk just laughs it off!

In the episode, "Okmyx" is always pronounced as "Oxmyx", but in the script and canonically his name is spelt "Okmyx", so I used that here. But you can imagine in your head it's pronounced "Oxmyx".

Transcript

1
Captain's log, Stardate 4598.0. Federation ship Horizon explored the early industrial society on Sigma Iotia II 100 years ago, before the Prime Directive. We are to assess and repair any cultural contamination.
{surface of planet}
Kalo: You three, petrify!
Kirk: We're here to see Mr Okmyx.
Spock: Fascinating. Firearms.
McCoy: And hats!
2
{Okmyx's hangout}
Okmyx: The Horizon Feds left us The Book.
Spock: Fascinating. They've modelled their culture on gangster-era Chicago.
McCoy: Including architecture and women's fashion.
3
Okmyx: I need a hundred of your fancy heaters to knock off the other bosses.
Kirk: No way.
Okmyx: Put 'em on ice!
Spock: Ah, now I see the need for heaters.
4
Kirk: I'll distract and confuse our guards by teaching them Fizzbin.
Spock: Magic: The Gathering might be more effective.
5
Kirk: Bones, Spock, you beam up. I'll try to deal with Okmyx alone, and get myself captured by his rival.
6
{Enterprise bridge}
Okmyx: {over radio} Krako's got your captain. Come down here and I'll help you bust him out.
McCoy: Can we trust him?
Spock: He's a gang boss, of course we can trust him.
7
Caption: Spock and McCoy get captured the instant they beam down.
{Okmyx's hangout}
8
Kirk: I escaped. Let's put on local clothes and do some more pointless running around to pad this episode.
9
Kirk: I'll adopt their slang.
Spock: The dialect is nearly 400 years old. Equivalent to a 20th century person adopting Shakespearean slang.
Kirk: Not a problem, guv'ner. It'll be gnarly.
McCoy: Nice hats.
10
{a street outside}
Kirk: Let me operate this mechanical conveyance. I'll show these benighted jackdaws a far out thing or two!
Caption: Car goes backwards.
Caption: It's a clever metaphor for the plot.
11
{Okmyx's hangout}
Kirk: Us Feds are muscling in. You dudes make love, not war, or else we'll shiver your timbers!
Okmyx: Uh, sure... I guess.
Kirk: And we want a piece of the action. A 40% cut of your planet's economic development.
McCoy: Nice. And some of those hats.
12
{Enterprise bridge}
McCoy: Uh oh, I left my communicator down there.
Spock: They will discover the principles of all our technology. If they imitate it, they could demand a piece of our action. We must retrieve it.
Kirk: Naaah, leave it there.