I'm not a native speaker. Is it a vulgar word? Didn't seem like that to me. And I didn't know people looking to lose weight wanted to do so specifically without gaining any muscle. My advice wasn't to become a body builder, just a healthy person.
I'm guessing the negative comment was due to a jocks vs. nerds cultural thing, combined with the fact that your advice was well.. bad.
I'd argue "the best first step" is not to start pumping iron, but to develop and execute a strategy that helps you to reduce your number of daily fork lifts.
