That's true.
Copyright is the set of prerogatives conferred by legislation to any natural or legal person who has created an intellectual work, and serves to ensure jurifically that the use of the work and its respective benefits are the creator, under penalty of suit in case of misuse.
However, there are some situations where US law authorizes the use of copyrighted works by third parties, depending on the purpose.
The perimited purposes are educational, cultural, critical and incentive to research and dissemination of knowledge, and it is prohibited to use for profit and commercial purposes.