My own view in this jam is to give 1 star if there's no story, but mainly because of 2 reasons:
- In this jam, the overall is a chosen rating, not an aggregate of other categories.
- The second is that a game that doesn't require or have a story should not expect to recive a good story rating as the design of the game did not have a story. This is just my personal view, for example, my own submission did not have sound effects, so I wouldn't expect my own submission to be rated highly on SFX.
In a jam where the overall rating is automatically defined, I might approach this differently.
At the end of the day, what ratings you give is based on your own perceptions of the game, the work you feel has gone into it, and what you think is an appropriate rating. Everyone's opinion is different and is based on their own perspectives.
When the results are tallied at the end, better games tend to get better results regardless of what 1 person has voted. Itch also tries to use a bit of math to adjust the final results to balance them against the number of ratings you received to further reduce 1 or 2 errant votes from seriously hurting a submission.