Source of the story 

ive made some minor changes to the paragraph, it isn't questioned as a source for hadith, it isn't accepted outright as a source of legislation since the only source is Ibn Ishaqs history. no history irrespective of the author is used for doctrine in Islam and all works of history take a back stage in terms of authenticity [since historians did not bother to document their works] to the works of hadith literature such as bukhari. the current phrasing made it seem as if their existed a dispute between various scholarly schools of thought regarding the narration which doesn't exist, the grading of this narration is unanimous since it never made it into any works of hadith literature. The wording also seemed apologetic which Muslim scholars would never have been regarding the actions of the prophet, they would have accepted it and used it to legislate if they deemed the source reliable. Two issues are missing in terms of context, she was calling for his assassination during a time of open warfare and she was doing it via poetry which is considered the highest form of publication among the Arabs in those times as the entire society revolved around oral tradition and poetry. Poets had a place higher than tribal leaders in that society, and where often feared as well as praised [for the good or damage they could do to a persons reputation]. To put it into a modern context this would have been the equivalent of Khomeini calling for the assassination of salman rashdi in a time of war and not the image of a little girl who writes poetry.