Is spyware, which is a type of advertising on the internet could be illegal?

Spyware known as Advertising Supported software (Adware) is a way for the authors of an online downloadable product to make money without selling it to their users. Many large media companies offer them to place banner ads in their products in exchange for a portion of the revenue from their banner sales. So the user doesn't have to pay for the software and the developers are still getting paid. In this case, U-Haul is suing …

…to download the spyware when downloading a shareware program. Which I agree one hundred percent because it's saying the user wants to download the pop-up's to get advertisements to find cheaper and better deals, which is actually not true (because why would a user want to download ad's onto their computer and get pop-up's on every site they visit) but if the user is downloading that spyware program that is what it is logically stating.