It's not that they would have been more subtle, just that "crap", "shit", "damn", and "hell" were more shocking back then, and the F-word, the C-word, and Mr. Wu's favorite word weren't as much in circulation until later in the 19th century and into the early 20th. Basically, Deadwood takes place near the time when profanity in the English language was transitioning from blasphemy to sexuality.