Because a vpn can monitor all the websites that you visit. Not directly what you're looking at, but definitely where you're looking. Just line your provider can, if you're not using a vpn. But at least with your provider, you have a contract with them - you pay them to transport your data and nothing more. Some very scummy providers aside, that's where it stops.
A free vpn, however, needs to pay for transporting your data somehow. And if you're not paying for it with money, then who/what is?
It's not even free, the service itself is a payed subscription. But it's there and it could be working and funneling data without the user knowing it if they wanted to.
Because a vpn can monitor all the websites that you visit. Not directly what you're looking at, but definitely where you're looking. Just line your provider can, if you're not using a vpn. But at least with your provider, you have a contract with them - you pay them to transport your data and nothing more. Some very scummy providers aside, that's where it stops.
A free vpn, however, needs to pay for transporting your data somehow. And if you're not paying for it with money, then who/what is?
See also Tom Scott's explanation about vpns, why you probably don't need one, and why he refused their advertisement money.
Here is an alternative Piped link(s):
Tom Scott's explanation about vpns
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I'm open-source; check me out at GitHub.
It's not even free, the service itself is a payed subscription. But it's there and it could be working and funneling data without the user knowing it if they wanted to.