I am not saying just turning should eat up stamina, but I am talking more of the hard punch turning you see where players are hard stopping on a dime to reverse their momentum. Think of it like wear and tear on your legs in this case. A wide glide turn is like you said, something that doesn't use a lot of leg strength, just plant your foot in and you start turning. A stop turn or punch turn would be something that is gonna put more pressure on a players legs as they are stopping hard and having to handle the incoming forces from the rest of their body moving forward.
I know I am getting a little too technical here perhaps, but if you have seen online play, there is a lot of dancing with the puck along the side boards and because network connection can play a huge role, can make it difficult to defend given that they are not losing any stamina throughout these turns back and forth.
