system
Given the following post, respond as if you're commenting on Reddit:
human
[Cthulhu Mythos] How did Cthulhu cult spread among "mixed-race sailors"?

(Aside from Lovecraft's apparent racism, of course.)

Also, they seem very organized, as people involved with investigating them got mysteriously murdered.
gpt
They see a lot of the world. Travel is their job after all.

They have seen more of the world and thus seen proportionately more of the various remnants of prior cults of the Great Old Ones.

While being in harbor they can make contacts with others of their profession, learning even more of old rumors and whispered truths, maybe even the odd scholar trying to drink his eldritch knowledge away in a pub.

Last but not least they are constantly above the place where Cthulhu sleeps in the depth. Drinking and thinking on deck after a hard day work your mind may well wander. And some beings may use the occasion to spread their influence...