His use of the word ‘useful’ implies he classifies things as ‘useful’ and ‘useless’ according to some absolute value system that he considers evidently true but that in reality is no more or less valid that those things he lists as merely useful.
Yes, we know, opinions are like assholes, everyone has one. You don't have to believe him or agree with anything he says. That's ... how it works.
I generally find his posts quite helpful and useful. Even ones where I might not agree with him.
Your comment is noise. It's just blind criticism without actually saying anything. I don't find it helpful or useful. "His value system could be valid or not valid". Also, water is wet and British food sucks.
Also, I really don't understand why your comment is so biting and aggressive and how you finding his posts helpful and useful is responsive to GP's point? Did GP offer some general critique of his posts? Maybe GP also finds them generally helpful and useful, but had a point to make about this specific post? Your entire response is generally strange and the rudeness is unwarranted.
Sivers' perspective is subjective. As most opinions are. So even if he is implying an "objective truth", none of us are obliged to treat it that way. But that isn't specific to Sivers or his above post. That literally applies to everybody.
Again, it's like saying water is wet.