Elmundo newspaper is a liberal oriented newspaper and they have their audience. Trying to milk the maximum level of outrage about anything done by evil socialists is expected for they.
Thus, take in mind that the real situation could be (and probably will be) a little less melodramatic. Some of their journalists and their director have been fined for spreading difamatory, partial or even faked news in the past.
They basically steal public money by not contributing taxes, so that general population (=we) has to pay up the rest via increased taxation, or public welfare, education, medicine, research, social system etc. suffers because of lack of funds.
Increasing net worth at all costs of types like Bezos, Zuckenberg or Brin at the cost of everybody else is not in interest of humankind in any imaginable way.
The Conservatives in the UK are planning a similar tax, they are certainly not a socialist party.