The statement is generally true. Television viewers are often passive because they are not in control of the content they see. They are exposed to advertisements whether they want to be or not, and they may not even be paying attention to the ads that are shown.
On the other hand, Internet users have more control over the content they see. They can choose what websites to visit, what videos to watch, and what ads to see. This means that marketers have to work harder to reach Internet users and to get their attention. It can be more difficult to get Internet users to pay attention to advertisements because they are actively making choices about what to see and what to ignore.
Overall, television viewers are generally considered to be easier to reach with advertisements because they are passive viewers, while Internet users are considered to be tougher to reach because they are active users who have more control over the content they see.