I get quite concerned about the alleged degree of subjectivity of pilots (as expressed in this forum) and ice. The idea was to reduce this subjectivity (not elliminate it).
That said a lot of data and analytical thought has gone into the FCOMs etc. provided by the manufactureres to the operator. Hopefully the operator has adopted these (as approved by his regulator) in what he presents to his crews.
It's not sufficient nor productive for us to argue about the pros and Cons of a subjective judgement if it has already been covered in the SOPS presented to the crew.
The issue is either a violation or a regulatory review of the SOPS of that operator.
I would push for the latter and respond only to that once it has been completed.