This is not a good video on the subject.
His stance is that synthetic oils suspend soot and other sludge forming particles, while conventional oil does not. In actuality, it's their tolerance of heat that reduces sludge buildup. But this isn't included in the speech. Then a ton of anecdotal car parts with sludge... yada yada yada...
Fail.
There are plenty of good reasons to use syn, but these are ignored in favor of one that probably isn't even true.