At 13m in, he uses the fact that around 10% have turned on DNT in theri browser as a proof that people actually care about tracking, but haven't multiple browsers started turning on DNT by default?
Yes Microsoft enabled it by default in their browser (can't remember if this was the days of IE or Edge) and advertisers used that as an excuse that "DNT doesn't represent user choice" and that they could ignore it.
Safari is removing (or removed already?) DNT simply because websites are still tracking visitors regardless if DNT was enabled or not.
Just confirming, it was already removed!
And because DNT was used as an additional data point to fingerprint the browser and enable more tracking.