The generally accepted range for genetic influences is much higher -- say 50% to 2/3 although we know little as to which genes do what when it comes to something like intelligence.
Who's being misleading here? That "generally accepted range" you're trying to invoke is precisely was is being studied here. And it was wrong, largely because the people generally accepting it were confusing social factors with genetic ones.
they used multiple validation cohorts, they controlled for environmental factors, they controlled for non-autosomal factors, applied multiple methods to boost the predictive performance of their model. adding more snps typically leads to an overfit and poor performing model on validation cohorts, which is why they use so much rigor and end up with usually 100-400 snps for each of the phenotypes.
in anycase they found a lot more than 10 SNPs, and they did more than one analysis in the paper.
Parent educational status is a significantly better predictor than the polygenic risk score for educational attainment. heritability (also known as r^2) for cognitive performance they estimated at an even lower ~7-10%.