Why do chefs in cooking shows not always seem to do things the "right" way?
I have a couple of observations:


"Different" doesn't always mean inferior.
"Best" from a science perspective, doesn't always mean most expedient in a restaurant or home kitchen.
Sometimes the results of the difference between "scientific" best practice, and alternate restaurant or home kitchen practice are not noticeable, unless you compare these results side by side.
There are lots of ways people learn how to cook, and many practices have been handed down through generations.  While science is, naturally, the basis of all cooking, it is only relatively recently that people have taken a "scientific" look at cooking and shared those practices widely.


So, you are probably hearing more about "best scientific practice" these days.  However, old understandings and practices are hard to give up. People typically use the practice they were taught, because it has worked for them.