The IRS is not an official branch of the government, so why do we pay taxes?

Uh, you're wrong. They're part of the federal department of revenue.

Because it's the law. Your statement is classified as a frivolous argument--that is, wrong, wrong, wrong.

1. Contention: The Internal Revenue Service is not an agency of the United States.

Some argue that the IRS is not an agency of the United States but rather a private corporation, because it was not created by positive law (i.e., an act of Congress) and that, therefore, the IRS does not have the authority to enforce the Internal Revenue Code.

The Law: Constitutional and statutory authority establishes that the IRS is an agency of the United States. Indeed, the Supreme Court has stated, “[T]he Internal Revenue Service is organized to carry out the broad responsibilities of the Secretary of the Treasury under § 7801(a) of the 1954 Code for the administration and enforcement of the internal revenue laws.” Donaldson v. United States, 400 U.S. 517, 534 (1971).

Pursuant to section 7801, the Secretary of the Treasury has full authority to administer and enforce the internal revenue laws and has the power to create an agency to enforce such laws. Based upon this legislative grant, the IRS was created. Thus, the IRS is a body established by “positive law” because it was created through a congressionally mandated power. Moreover, section 7803(a) explicitly provides that there shall be a Commissioner of Internal Revenue who shall administer and supervise the execution and application of the internal revenue laws.

The IRS warned taxpayers of the consequences of attempting to pursue a claim on these grounds in Notice 2010-33, 2010-17 I.R.B. 609.

"The IRS is not an official branch of the government,"

You have received at least one excellent answer.

Since you did not reply to it, here is a more simple answer.

That is utter BS made up by idiots. The IRS is part of the Treasury Dept. You were lied to.

"so why do we pay taxes?"

Its part of being American. There is no free ride for anyone. No matter what idiots tell you NO ONE, barring children, is not paying taxes. Even Trump pays some taxes.

Some people have no comprehension of social responsibility. Those need the threat of incarceration and confiscation. They are not heroes, they are sociopaths.

Try being a responsible American. If you hate government and taxes move someplace without that.

Somalia.

Where all Libertarians should move to or study to learn just what that system for aliens leads to.

the IRS is a part of the Dept. of the Treasury and anyone who told you it is not a branch of the gov't is an idiot

We're all born stupid, but have to work VERY hard to remain that way. Congrats on your hard work! Not that you accomplished anything worthwhile, but so it goes.

What rock did you just climb out from under?

Seriously what are you 16 ?
Ask ur parents WHY.
Or even READ about WHY in libraries internet.