The name itself is fine to use, when talking about it.
You can talk about how you like Steemit or don't like Steemit. That does not detract from their intellectual property right to promote their brand their way.
However, let's say you wrote a blog post, and said "Hey everyone. A new Steemit Contest"
...at that point, you'd be using their brand name in a way that they did not intend or authorize and in my opinion, then that is when it could be a problem.
Similarily, if you were to use their name in the same color, and font, and print it on t-shirts... or even posters... that would be wrong, because no one has the right to market or use their brand for promotional purposes but the person who actually owns the brand.
So feel free to use Steemit in your text and dialog... just not as a way to market, or promote things.