Peaks on DS helmets aren't as big as peaks on MX or off road only helmets. They are certainly nothing like the "duckbill" peaks we used in the 1970s.
Peaks are made of relatively light weight plastic and they will shatter or bend on impact with the road. They simply are not strong enough to act as a fulcrum that story is just some sort of old wives tale rubbish from somebody who doesn't like peaks.