Maybe people talk like that, but in my opinion Barca has a much stronger team than Real, Ansu Fati provides great games, Griezman has yet to show what he knows and with Messi it is an amazing trio with having Coutinho as an assistant, Real struggled a lot previous the game may be a good environment and defense, but they are hampered by the attack.
Much stronger?! I disagree if you state "much stronger", how can? Real Madrid also has good players and they are possible to win el Classico. For me, Barca only has Messi in the front line as the most effective striker after Suarez leaves. While Real Madrid has no big difference in their main players. Both Barca and Real Madrid have the same chance to win in el Classico. Don't underestimate Real Madrid, they the winner last season, right? 
And Real Madrid? They are doing great but time will tell us what will happen, Barcelona is building from zero right now, will it end up as Phoenix? Who knows...