Ask HN: Watch YT on Firefox but not Chrome unless I turn on history?

In Firefox, not signed in, I can watch videos. In Chrome, I can't see any videos listed, it wants me to turn Watch History on.

In Chrome, if I try to sign out on the YT page upper right (since it works in Firefox without me being signed in); it also signs me out of Chrome and pauses sync.

What's all this about?