Walaikum salaam.
There is no mention of ‘blasphemy’ in the Surah regarding 'Abu Lahab'. I am somewhat surprised to learn that 'Quranists' make use of such inferences and stories when they generally disregard secondary source narratives altogether.
Not withstanding any generic wisdom that can be extracted from the verse, it is clear that the narrative is very context specific and the details would be known to the addressees but to which the Quran did not consider elaborating for all humanity. God does not run out of words (31:27) and if the details were absolutely necessary for mankind's guidance, they would have arguably been narrated.
This would be no different from the context driven narrative of Surah Quraish (106:1-4)
I'd like to share a somewhat related article for your perusal, God willing.
UNKNOWN TOWNS AND NAMES - WHY FILL IN THE GAPS?http://quransmessage.com/articles/unknown%20towns%20and%20names%20FM3.htmI hope that helps, God willing.
Joseph.
UPDATE BY QM FORUM MODERATOR13th March 2013
This thread is now closed and a direct link to this post is now available at the dedicated Q&A page.
http://quransmessage.com/articles/q&as%20FM3.htmThanks.