If you think user privacy is "no reason", this thinking is exactly the problem with the online advertising.

Privacy is a right. Ad-tracking is not.

It's not just privacy! When I want to share an article with someone, I don't want the link to have 1000 characters with urlencoded arguments! On mobile I often do it manually and it's very annoying!

The reason is avoiding tracking, whether you agree with it or not, though.