Contrary to their whitepaper claims, Steemit is not just to talk about Steem. Nor is it only English (look at our kr and spanish tags, for example). In fact, I just did a quick check vs. Reddit, there are actually more posts being made about Bitcoin on Steemit than there are on the top Bitcoin subreddit. If the authors checked the tags they'd find posts about every crypto here, and posts in every language.