He used the word "euphemism" because that's the word the Society always used. They definitely did take the position that it would be wrong to use swear words--or even these commonplace words like "Gosh," "Dang," etc. But it's also true that these euphemisms were used within those in the congregation pretty commonly. Usually you wouldn't get a double take by saying, "Gosh" or "Heck."
Now, "Damn," "Hell," and the S and F words? Off limits. I do remember finding that some in my group of friends had decided that the word "pissed" was apparently okay to use. But I didn't.
I also remember when we hosted a bunch of friends from all over the world a few years ago. There were two brothers from Sweden who we were with one night, and we'd gotten into a discussion of beer. In his unsteady English, he said something like...
"Most American beers not goot. Ischit."
I was, like, "What?"
"Schit, schit. You know?"
It was so funny and inspired a whole conversation about curse words. Another brother from my congregation helped him to understand that this was NOT a word he should be using. But I wanted to discuss swear words, and their origins. I had heard that a very bad swear word in German was Schweinhund, which I'm told means literally "Pig Dog." It's funny to me that saying something like pig dog could be taken as profanity. And it made me wonder if there weren't parallels within the English language.
For instance, in this country, there is one word we use for feces that is socially acceptable. No problem with it. Another word is a little iffy, although not too bad. But then there's another word for the same thing that is absolutely socially unacceptable. Who decided this? Doesn't it strike you as kind of funny?