There are many claims made for olive oil. From its good for your skin because of its high levels of vitamin e or its anti-inflammatory properties or its help in reducing cholesterol levels.
Maybe one of the reasons for this is that it is a very natural product. Nothing is added and nothing is taken away. When you buy a bottle of olive oil that is all there is in the bottle - no additives, no preservatives nothing more.
Also when olives are pressed the process is clean. The fruit is crushed and then water added and then the mash is spun at great speed to separate the oil from the pulp residue and then finally the water naturally separates from the oil.