Anthology Books Available
Odds and Ends
2 5, 4:42pm
The reason usually given for the massacre was that Æthelred was prompted to it in response to the decade plus of Danish raids and fear that the large Danish population in the north would join the attackers. Although as you say there's a lot of dispute about how extensive it was and even whether it was directed not so much at Danish subjects of the king as against mercenary Danes who had turned on the English.
As you say the idea of a reaction against the 'too clean' Danes is probably artistic license. Especially since that chronicle was written in Norman times so there might have been some desire by the rulers to further degrade their subjects.