Some people think there is no law requiring people to pay federal income tax. Some people think the federal income tax law is unconstitutional.
The law does require the filing and paying of income tax. The Supreme Court says it is constitutional. Their opinion is the one that counts. Thinking the law is unconstitutional is not a legal defense for non-compliance. Believing that there is no requirement to file or pay might help avoid a criminal conviction for "willful" noncompliance, but don't count on tax paying jurors to help you.