Here's the thing. You agree to let those companies do that. They provide you with a service, and in exchange they collect data about you. That's the trade you're making. Without that data, they can't make any money as they rely heavily on advertising.
I think if you make the developers life harder and ask them to abandon the pull request and submit another you'll run in to objections.
I think the whole idea of pushing commits to an open pull request is a good one because you can see the discussion and the commits which come after it.
GitHub actually does this nicely by showing it in a timeline where you have a comment and then a commit following it in the discussion thread.
The core idea here is that underlying every data type is a number and presentation of that data type can often lead to it being interpreted and used incorrectly.