Because you are allowing company B to technically enter your home. But for them to do that wouldn’t Company A need a warrant for using Company B to enter your home? The same way as far as I know get a warrant to search pedo’s devices and entering home. I definitely know they need to have a warrant to tap your phone and stuff.
I would but none of them are free anymore.
I wouldn’t trust a free VPN. They’re still making money off of you just in ways that aren’t clear.
Paying $5 a month is better than having your internet service cancelled and this is the best case you might encounter.