Should there be an income tax? how is it enforced despite the fact that it's unconstitutional?:
There is no provision in either document you cite which says keeping all the fruits of our earnings is a part of freedom.

Now, our founding fathers were involved in colony govts before they were involved in rebellion.  In Virginia, our house of burgesses provided money every year to every widow and orphan.  We also applied our tax money to construction projects for the common good.  We also had courts to help protect our rights.  

When we had our revolution, we were opposed to taxation WITHOUT representation, we were not opposed to taxation.  We never have been.

You have a pretty limited view of humanity and our responsibility to create a just society.   Plus, you seem to be basing it on parts of our founding documents which don't exist.