Poncho,
Your first question was regarding the legality of the income tax. I posted copies of the tax code justifying its legality. You questioned the constitutionality of the code. I posted a copy of the appropriate constitutional provisions. Now you ask, if it is legal why won't they just answer our questions.
First, they have answered you questions by publishing the tax code. That is the law. It was passed by Congress. Second, it is not the responsibility of Congress to answer your questions regarding questions of law. It is the responsibility of the courts. Third, Congress empowered the IRS to administer the laws it has made regarding taxes (the tax code). The IRS then intereprets and implements the laws. Again, their function is not to answer your questions except as pertaining to your tax return. If you don't like the answer, they are not required to give you reasons. You may go to the courts for interpretation and redress. That is their function. That is why you must bring lawsuits.
The IRS is not the final word on interpreting the tax code. The federal court system, composed of the U.S. Tax Court, federal district courts, the U.S. Court of Federal Claims and U.S. bankruptcy courts, all have the power to decide, on a case-by-case basis, how Congress intended the tax laws to be applied. If more than $50,000 is at stake, a taxpayer can appeal a Tax Court decision to a circuit court of appeal, and in rare cases to the U.S. Supreme Court.
http://www.nolo.com/lawcenter/ency/article.cfm/ObjectID/AC7C25CA-0785-4A5D-B9523A9F215560A1/catID/2A0609A8-61F1-45AC-812194D5661BFE9F
Now, having said all of that, please keep in mind that I am not a lawyer and have not studied law. But it is common sense. I may not like it, but I do live with it as long as it does not violate my faith.
Finally, the First Amendment does give you the right to redress a grievance. It is call the court system. Thus the reason, again, that you may go to tax court for a final interpretation of tax law as administered by the IRS. Redress does not mean the courts will take your side. It does not mean you are right. It does not mean you will win your case. It may mean all of those things or it may mean you are wrong, you will lose, and the court takes the side of the IRS.
Hope this answers all of your questions.