No, taxes are not illegal. In fact, they are an essential part of any functioning society. Without taxes, government wouldn’t be able to provide the services and infrastructure that we all rely on.
Some people argue that taxes are unconstitutional or unfair, but that’s a separate issue. The legality of taxation has been upheld by the Supreme Court on numerous occasions.
So if you’re ever wondering whether or not you should pay your taxes, the answer is almost certainly yes. Unless you have a very good reason for thinking otherwise, it’s always best to err on the side of caution when it comes to the law.