The system is designed to favour wealth over income. Income tax vs capital gains tax is a good way to demonstrate that.

Another example of this is how homeowners are treated vs renters. Specifically, in terms of tax breaks for mortgage interest payments, expenses incurred during major home improvements, etc. Also you can withdraw a decent chunk of money from your IRA early without the hefty penalty if the withdrawal goes toward buying a home. On the other hand, renters are not eligible for any such benefits.