Did you know? Despite claiming to block all cross-site cookies out of the box, Firefox automatically allows Google to use them in your browser should you log in to one of their services.
The browser only lets you know about this once it happens, and it's on you to notice the permissions icon appearing in the URL bar. There is a link to a paragraph on a help page explaining this behaviour, but it seemingly goes unmentioned pretty much everywhere else on the internet.
This surprised me, especially considering Firefox's stance on privacy. I was even more surprised that this is done without consent. If this is for usability, Firefox should at least warn the user before this happens.
Take it you didn't click "learn more"?
To sign into YouTube, you need to sign into Google.Com. that's the cross site script. Nothing scary, or unexpected.
But that's one of the most dangerous trackers afaik. There should at least be an option to disable it.
Bingo! This is the way. I only open chrome when I need to log into a google/ alphabet site on the unlikely occasion. And close it immediately after.
Exactly if it can be used without logging in you don't have to log into everything.