I think that actually supports my point. A customer has a relationship with the ISP and can actually sue them. If people start putting google or cloudflare DNS into lots of devices and apps and those start doing something questionable then you have no recourse and even if they did they'd have to go after dozens of different vendors to change their behavior instead of the single ISP.
It doesn’t matter to the device OEM when the customer demands a refund because the device stopped working, even though the root cause is the ISP hijacking the DNS request and the device OEM has nothing to do with it. Easier to work around this apparently common ISP practice.
