"FLoC cohorts will comprise thousands of users each, so a cohort ID alone shouldn’t distinguish you from a few thousand other people like you. However [a tracker now] only has to distinguish your browser from a few thousand others (rather than a few hundred million). In information theoretic terms, FLoC cohorts will contain several bits of entropy—up to 8 bits, in Google’s proof of concept trial. This information is even more potent given that it is unlikely to be correlated with other information that the browser exposes. This will make it much easier for trackers to put together a unique fingerprint for FLoC users."
"as your FLoC cohort will update over time, sites that can identify you in other ways will also be able to track how your browsing changes [...] a FLoC cohort is nothing more, and nothing less, than a summary of your recent browsing activity."
The second paragraph you quote is literally the counter example of what I just said.
There needs to exist a way to identify you in other ways and in the future cookies won't be one of those. So a site that has your information because you shared it with them will be able to see your cohort changing, otherwise you'll look like a new user each time.
And yeah I'm extremely familiar with FLoC, more so than the EFF.
"as your FLoC cohort will update over time, sites that can identify you in other ways will also be able to track how your browsing changes [...] a FLoC cohort is nothing more, and nothing less, than a summary of your recent browsing activity."
https://www.eff.org/deeplinks/2021/03/googles-floc-terrible-...