I pay my ISP a lot of money each month. They don’t need my data to be profitable. Facebook, on the other hand, has a business model completely dependent on selling advertising based on my data to 3rd parties.

off the top of my head, AT&T and Verizon have done various forms of customer tracking for advertisers. They both used supercookies at some point, which were injected into customer egress, and ATT used to inspect web traffic in order to target ads (opt-out with a monthly fee, of course).

Certainly, if ISPs can access your data, they would like to. Its basically free money. But its not a life-or-death situation for them, and thus my (somewhat uneducated) guess is that there is less management focus on things like deep packet inspection and consumer targeting. They can also jsut jack up prices or sell more subscriptions. At Facebook, on the other hand, selling ads is priority number 0. Its the only way to make money. So I'd worry more about Facebook seeing my traffic.

However that happened in America, land of the greed. If you're from other countries, I think the point still stands.

Exactly. It's terrifying how many people still don't get it, no matter how many times it is repeated - you are not a customer, you are a product!