That is exactly right. It says we will monitor you. But it doesn't tell you what they monitor. Most users will believe that they are just monitoring what websites you go to, not what passwords you're using, what secure sites you'll be visiting. Most users aren't going to realize their traffic will be routed through Comscore's proxy server.
You don't think they're being decietful. Let me point out that telling half truths and misrepresenting what you are actually doing is still lieing.