Why is this post unfair?

I am confused as to why post #1208399 is in the unfair pool. It would be nice if I could hear a reason or see a response.

It looks like Suwako is about to attack the frog. Being a "frog" herself and much larger, it's unfair to the little one. Only thing I came up with. Though most of those pools are a bit silly in their requisites anyway.