Tone in The Odyssey
Homer combines a serious tone with the enchanting and beautiful tone of a lyric poem. His subjects are gods and heroes, meaning he must approach his topics with appropriate gravity. However, there are some movements of levity, as this was an oral story that had to entertain as much as it instructed.
In addition to the somewhat foreboding presence of the temple of Poseidon, this is another ominous statement about the Phaeacians. While it could be that Nausicaa means that they might be critical, the term ill natured implies that they might be mean or hostile, especially considering that it's been made clear that they don't like strangers and her worrying about her reputation.