I dislike the trend among computer users that query strings == tracking data. They're just one of the many ways a browser request can contain data. They are used for all sorts of things in perfectly valid websites, and it's difficult for me as a developer to just just arbitrarily accept that a certain feature HAS to be used for a certain malicious technique, despite it being common.

With more limited copy-paste functionality, tracking parameters could just as easily be put in the request body. Or a cookie/session data. Or, if you're nasty, you could get everything you want to know out of a user via fingerprinting with very little up-front data at all.

We as users have basically already been collectively pwned, the solution being to use VPNs, anti-tracking scripts/extensions, encryption, and just plain ol 'stop using services that track you'. The preceding are all leagues better for one's privacy than superstitiously chopping up a URL.

Honestly, disallowing other websites from from adding their query strings to your URLs I think is awesome, and I think it makes sense that websites should validate their URLs against their internal APIs only. But, given this was only done for query strings, and not other parts of the request, I still feel like this whole thing establishes more of a taboo than an actual security or privacy guideline.