The rub here is you needs those goods asap, and noone in your FS is on for another
3-4 hrs, but you have a local that always has offers and you can grab them instantly,
but they trade 1star ... .. [emphasis added]
This is exactly the scenario that makes believing the assigned value of the goods should be taken as the "correct" value. The devs don't, and can't include in their valuation of goods the intangible and situational pressures on those values. Thus, the goods being traded -- the ones offered -- in that situation and to the buyer, are worth 8% more than the system says they are worth. And to the seller they are worth 8% more because he/she understands that in the current state of those goods (supply and demand) it's highly likely (or at least more likely) that some player will pay 8% more for those goods. This is the true nature of any human trading system, real or imagined. The value of the trade is determined by the traders, not the system. And if the system encourages moral judgements about the players because they recognize this and use it, it is not being fair to them at all.
So I continue to agree with your analysis. It would be better, in my opinion, if everybody quit using the star system as a moral measure of other players. Just because the star system calls a trade "unfair" or "fair," it doesn't mean that in the circumstances of those trading, it is such.