why do libertarians ignore 16th amendment?

they are willfully blind to the fact that the constitution has been amended to allow for income tax.

A tax on one's income is immoral and illogical.  It's like being penalized for working.  And it's essentially done at gun point.  Don't pay, you go to jail.  Absolute faggotry of the highest degree. 

Federal income tax is basically like a school yard bully demanding your lunch money.  He has no right to it, but if you don't give it to him you'll get beat up.

I'd invite the government to do 1/4 of my work for that 1/4 of my paycheck, but then that shit would never get done.