Thanks, but I still dont get the meaning. I thought, in the past, that 'about what ought to be' was a bit closer, but it does not seem to apply this time.
In your answer, I cannot see what norms they are talking about.
'Even statements that appear to be simple descriptions can conceal important assumptions relating to norm
I cannot say what the norms might be - that would be made clear in the wider context of the full text. In this context, they are possibly the social rules underlying the particular aspect of social behaviour being studied or analysed.