Impossible to say why that they rated it as poor- and such empty feedback really doesn't help an artist. As comic illustrations with captions go I believe it is effective- perhaps they did not understand your purpose, or they did not see the humor.
This artwork was given a poor rating after being posted to another art site. NO comment was given for the poor rating. The only conclusion I can come to is that the rating was given because of content. What do you think?