Ultimately the score comes down to
0 - Pts for a poem that has a bug in it (some error message or unspecified words)
1 - Pt for a poem that doesn't fit a theme
3 - Pts for a poem where the words "match a theme" (animal, nature,...)
But it can be hard to tell if they match or not and sometimes those that don't match can be more intriguing than those that do.