There are some things you cannot contractually agree to in most countries. A government would also intervene if I agreed that you can kill me to harvest my orga

There are some things you cannot contractually agree to in most countries. A government would also intervene if I agreed that you can kill me to harvest my organs if the money goes to my family and similar scenarios. It's an interesting ethical debate where the lines in the sand should be drawn (or if there should be any lines at all for that matter) but traditionally some lines exist and there are some things governments feel they need to control on behalf of consenting adults. Additionally it's a question of discrimination laws in certain countries. If WA gave you the option of opting out but in return not being able to use their service at all that could be seen as discrimination. If you take the stance that personal information are a very essential good that isn't all that unreasonable (once again I'm not making a value judgment only a logical one). I believe in most societies there's a somewhat solid majority support for the idea that government sets some rules for the marketplace. How many/if there should be any is open for debate but these frameworks exist and are typically backed by majority votes.