Over many years, I've come to know that "Design" is a very subjective field. There are efforts to make meaningful measurements, A/B testing, etc but the domain space of possibilities is so large that it is impossible to test all configurations - layout alone has endless possibilities and which layout is better? My guess is as good as the designer's. I need to be able to see either one of the following to consume the advice - 1) Deep logic that describes the fundamental problem, an unchained reasoning leading to the solution with little ambiguity or "gray areas". or 2) Concrete experimental or empirical data that a particular solution works while making sure things like accessibility are accounted for. Otherwise, how do I know that some authority in "Design" is correct and I should follow their advice?

I am just speaking my mind, what kind of things prevent me from trusting others despite of their benevolent intentions. Time and again, I've been bitten by bad subjective advice - there is a lot of bullshit out there. Tread carefully, adopt what makes sense to you and ignore others unless evidence shows otherwise. That said, there are a lot of gems out there as well.

If the thing I am making is art and is subjective, then why can't I just be original? If a particular activity is totally arbitrary, then all bets are off.

Blindly following advice is why we as a society get stuck in a local optimum and don't try other things. Domain exploration and experimention, originality and authenticity are paramount to getting out of the local optima. Every once in a while someone does and they revolutionize the world.