While saying that he doesn't get an opinion at all is wrong, it's not unreasonable for people to not want to take much stock in what he has to say.
Really? The guy who created the series, had to basically beg the studio to get his movie to made, endured production hell for it to come about shouldn't have much stock placed on his opinion? Nobody is more invested or more authoritative on matters Star Wars than this guy, even if you disagree with a lot of what he has to say and his choices. I mean, I know the prequels were awful but sometimes I think people have gone nuts when it comes to opinions on Lucas.
In any case, people should stop just reading the little quotes taken from the interview and watch it in full, he actually has a lot of interesting things to say on the industry even if a lot of his criticisms of the industry could actually be directed at a lot of his recent works.