I really don't understand the problem here. It looks like FLoC will entirely depend on the browser (which Google controls if it's Chrome). So the browser will analyze your browsing history (and since it's Google, it will probably connect to everything else Google knows about you) to request targeted ads.
But, what about the people who don't use Chrome? I would hope that most people who know what EFF is already don't. Firefox will surely come with a way to disable it, or you'll configure it to always send "my little pony" or something like this.
In the end, this seems to really be about Google (with a browser) competing against Facebook and other ad providers (who don't have a browser).
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