What do you mean “active?” It’s just a file on your computer. Reddit has to actively look for the cookie, which they can do if they have a “share on Reddit” button on the websites you visit. But Reddit doesn’t know all the websites you went to that don’t have this button just because you have a cookie.
What do you mean “active?” It’s just a file on your computer. Reddit has to actively look for the cookie, which they can do if they have a “share on Reddit” button on the websites you visit. But Reddit doesn’t know all the websites you went to that don’t have this button just because you have a cookie.