It's an average. Some people are going to bring it down, some people bring it up. I take a certain pride in doing my best to bring it down, but at the end of the day living in a capitalist hellscape, you have to concede it's going to get you at least a little.
Because it's not just clicking on sponsored Google links. You may never directly buy something sponsored, but by giving them your data, you give them demographic information to find people like you that might be more prone to clicking links, and that helps.