Both definitions are correct. When you sexually attack someone, you are interfering with that person and you are disturbing him. To put the matter another way, 'disturb' is the most general meaning, but the word 'molest' also has the special sexual meaning. Because the word has a special sexual meaning, it is better to use some other word for the general meaning. For example, you can use 'bother' or 'disturb'.

The basic idea of "molest" is touching in a way that is sexual and unwanted. Any other definition is uncommon and figurative.