I don't know why it's always a balance with teams that score too many goals, I mean their back seems to be always open and they concede alot which is not very good although it brings out the very best because it's like competition when they concede more goals but if they find the balance to have a strong defense line they would be far above most of the teams in la Liga even the giant Real Madrid.
Maybe the management concentrates and builds more on attacks and midfield. You before a team can get to the defence line, they need to go through the midfield line first and when a team has a good midfield, everything becomes easy for the attackers and the defenders. The defend less and attack more. So in this process they scored a lot of goals because the midfield is able to absorb the pressure from the opposition team and launch the ball forward to their own attackers who does the job. When a team builds it's defence, they hardly score goals in the process because all concentration is on the defence.