Oh, that is so unfair. There is no unfairness about income tax. Such a tax is imposed by the entire civilised world. It hurts you without your knowing it. It is invisible and hits all the citizens whether earning or not.
Tax is on income.
Inflation is a tax on Expenditure. Your same amount of money buys you less than what is bought last year. The difference is inflation. Value of your money has gone down to the extent of the rate of inflation. In effect, your investment has earned nothing.