Your argument is patently flawed. If ‘systemic failings’ were indeed contributing factors to the decision to continue to rather than divert, all that followed after the decision to continue must be attributed, in part, to those ‘systemic failings’.
And just to be clear: Until I hear a replay of the CVR, I won’t be convinced that the decision to continue rather than divert, after transmission of the SPECI, was an error on the part of the PIC.