Coyboys vs Weenies
Yes, yes... safety first. Of course, and no question.
Still, I've seen plenty of inexperienced weenies call for unnecessary deicing causing enormous expense and environmentally hazardous mess.
There is only one rule for ice that is applicable to safety and it requires that ice not be "adhering" to the critical surfaces and any others also deemed relevant to safety.
There are certainly plenty of rules being applied in different places that prohibit making a decision as to whether the stuff is adhering or is just loose and dry snow on a cold surface - you simply must apply a deicing procedure and not bother thinking about it. You can obey these rules and relax, or, if you are permitted to make your own determination you can do so if you possess the sense and experience to make a good one.
Maybe the crew in unfortunate question here determined the conditions were such that they had no adhering ice. I don't know and the details in the first post don't provide enough information to even make a better guess.
In short, enjoy your modern day rules designed to eliminate any possibility of a poor assessment of the conditions by an inadequate pilot and don't be so certain safety was jeopardized when somebody else operates outside of your own comfortable blanket of rules designed for the lowest common denominator.
I'm not saying the rules you operate by are wrong or bad, just that you may not know everything, mate, and its scary to watch you identify and condemn another aviator this way.