Why are fruit juices bought in the market are much clearer than the jiuces which are made in our homes?

Your friend is right. The packed juices which we buy from market have enzymes like protease, pectinases and amylases which digests the proteins and sugars of fruits present in the juice into simpler form and hence juice appear clear. At home we do not add enzymes so the proteins and sugars are in crude form giving dense appearance to juice.