most people access the site while they are at home, and how do they know people don't have college degrees?
Are you kidding?
We live in times where thanks to the constant commercial spying Amazon knows you are pregnant before you do.
Ever looked how many snoopers additional to Alexa are on mayor websites? Sometimes more then 100! And the chance is not bad that one of those is a hidden coin miner, running your CPU for you while you read a newspaper article or watch a youtube video.
I know, this is kind of scary. I wonder if they can deduce your education level based on your browsing history?
From just a week of what sites you have visited, you often can say age, gender, income, work, family (and hidden lovers), interests and a lot more.