Taxable profits are the difference between the income of a company and allowable costs. The company pays dividends to its shareholders, but the dividends are not allowed as costs; hence the company pays income tax on them. When they are received by the shareholder, they are again added to his income and taxed. This is double taxation of dividends.
Double taxation is unjust, and could continue only in a country which has an outlandish sense of justice. The socialists would believe that dividends go to the rich, and that taxing the rich is justice, whatever the grounds. This cavalier attitude is also reflected in the communists