The guy does have legit points.
Majka did win 2 stage, took 2nd behind Nibali while starting with contenders on the bottom of the climb (of course he deserved 3rd because Konig was stronger), and then showed that he can drop everyone but Nibali (including Pinot) on Hautacam. And that is after riding Giro and being called to TdF in last minute.
Then, instead of resting after being active for last 8 stages in TdF burning more energy than most GC contenders, he went on, rode two small races and 5 days later destroys the field (2 stage wins +GC is destroying the field) at another WT race. Yes, I would rate that way higher than Giro stage win. And entire gap that Aru had was due to MTT, and since TT hardly shows riders ability to win......
Majka >Aru in palmares so far and by a mile. Aru could turn out to be a better climber and overall rider, hopefully we will get to see next year if both are 100% healthy, but right now Majka is better.
Also, Aru seemed to be on a last gas at the end of Giro. He is young but since its the race he targeted I am not sure just how good his recovery is at this point (of course much energy was spent in MTT but still have my doubts whether he can hang on with better climbers in 3rd week)